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Mars Bar Brownies!

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Easy and Fudgey Mars Bar Brownies! So Chocolatey, So Delicious!

It’s the time to have something so chocolatey, that you’ll want to make them again and again. These Mars Bar Brownies is exactly that. So unbelievably chocolatey and Fudgey they are on a next level. Are you intrigued yet?

Anyway. I thought I would start this recipe post off with a statement that makes you go these MUST be good, and then you’ll see the pictures and be like oh heyyy look at them, yes, they are amazing. And I really hope you guys did because I certainly did. 

From the beginning I must say that Mars Bars in the UK, are Milkyway bars in the US, so if some of my American readers are a little confused right now, just roll with a Milkyway instead. I finally found out why there is a different in name the other day (due to a family spat back in the day), and I was surprised that that was all it was. 

Even so, Mars Bars are the one. They are slightly underrated in my opinion, but I do adore them. For those who have never experienced the wonder that is a Mars Bar… they are Nougat and Caramel, coated in Milk Chocolate. They are delightful. 

When I was thinking about what chocolate bars I should bake with, I wanted to use one I hadn’t tried in a while. I’ve used Mars Bars four times on this blog already, my favourite time being my Mars Bar Cheesecake, but it was so long ago! 

These brownies came about because of my craving for something Mars Bar, and also because they were on offer in the supermarket I was in at the time so that made the bake cheaper. Always handy in my books. I couldn’t resist! 

I went for a classic style brownie, that I have used in so many recipe posts now. And I will say it time and time again, PLEASE USE DARK CHOCOLATE IN THE BROWNIE MIXTURE. I don’t really care if you ‘don’t like dark chocolate’ it will make such a good brownie, and not too ‘dark’ a flavour, so PLEASE stick with it. 

If you use milk chocolate, the mixture is so much thinner, and when people moan to me that their brownies didn’t bake properly, and say they switched to milk chocolate then that is why. It doesn’t work the same, and doesn’t make them nearly as fudgey. Dark chocolate is the best. 

The key really is to make the brownie mixture as thick as possible, and dollop on all your Brownie bits. When the caramel and nougat bakes, it’ll make little pockets of deliciousness for you to enjoy, and they are just a combination to behold. SO tasty!

I realise its a faff, but freezing the Mars Bar bits before baking really is the best practice so they don’t explode everywhere completely and utterly, but its not completely essential. However, if you can, I would 100% recommend it! 

These brownies are so fudgey, so moreish, and delightful. I really hope they live up to your expectations for my latest Mars Bar creation! Enjoy! X

Mars Bar Brownies

Mars Bar Brownies!

Easy and Fudgey Mars Bar Brownies! So Chocolatey, So Delicious!
5 from 18 votes
Print Pin Rate
Category: Traybakes
Type: Brownies
Keyword: Mars Bar
Prep Time: 15 minutes
Cook Time: 25 minutes
Cooling Time: 1 hour
Total Time: 1 hour 35 minutes
Servings: 16 Pieces
Author: Jane's Patisserie

Ingredients

Brownies

  • 200 g Dark Chocolate
  • 200 g Unsalted Butter
  • 3 Large Eggs (or 4 medium)
  • 275 g Light Brown Sugar
  • 100 g Plain Flour
  • 50 g Cocoa Powder
  • 300 g Mars Bar (chopped & frozen)
  • 100 g Milk Chocolate Chips (optional)

Optional Decoration

  • 50 g Milk Chocolate Melted
  • Mars Bar Pieces

Instructions

  • Preheat your oven to 180C/160C Fan and line a 9x9" baking tin with parchment paper!
  • Melt together your Dark Chocolate and Unsalted Butter until smooth in the microwave or in a bowl over a pan of simmering water. Leave to cool for a few minutes
  • Using an electric whisk/stand mixer, whisk your Eggs and Sugar together for 5 minutes or so on high speed, or until the mixture has doubled in volume, is alot paler, and leaves a trail for a few seconds when you lift the whisk out.
  • Pour in the chocolate/butter mix and fold through very carefully.
  • Add in the Flour and Cocoa Powder and fold through carefully again.
  • Add in your frozen chunks of Mars Bar and chocolate chips and fold in. Pour the mixture into the tin and bake in the oven for 25-30+ minutes.
  • Leave to cool in the tin, and then enjoy!
  • To decorate your brownies if you fancy it... melt your chocolate and drizzle over the brownies, and add pieces of Mars Bar to each one! Set in the fridge, then chop up and enjoy!

Notes

  • Please try and freeze the Mars Bar first as it'll work so much better!
  • These will last for one week+!
  • You can use caster sugar instead of the brown sugar, the brown sugar just works really well for the Mars Bar theme!
  • If your brownies are taking much longer than stated to bake, your oven may have been the wrong temperature, or you over mixed your batter. Keep adding on 5 minutes till they're done and cover with foil if need be!
Nutrition Facts
Mars Bar Brownies!
Amount Per Serving
Calories 392 Calories from Fat 198
% Daily Value*
Fat 22g34%
Saturated Fat 13g81%
Cholesterol 69mg23%
Sodium 60mg3%
Potassium 207mg6%
Carbohydrates 47g16%
Fiber 3g13%
Sugar 35g39%
Protein 5g10%
Vitamin A 410IU8%
Vitamin C 0.2mg0%
Calcium 66mg7%
Iron 2.7mg15%
* These are only estimates and can vary dependant on brands of ingredients and serving sizes.

ENJOY!

Find my other Recipes on my Recipes Page!

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J x

© Jane’s Patisserie. All images & content are copyright protected. Do not use my images without prior permission. If you want to republish this recipe, please re-write the recipe in your own words and credit me, or link back to this post for the recipe.

About Author

Hiya! I'm Jane, and I adore baking, cooking and all things delicious. I'm also partial to homewares, lifestyle posts and more!

81 Comments

  • Bethan
    June 5, 2020 at 12:38 pm

    Hi Jane, Another question from me (turning into a complete lockdown baker and your site is a massive help for some seriously good recipes). when you freeze the mars bars, do you put them in a container??

    Reply
    • Jane's Patisserie
      June 5, 2020 at 12:42 pm

      Hey! Ahh thank you so much!! And no I don’t – I usually just chop them up and shove them in the freeze on a plate or in a bowl! I do have a few shelves in my freezer just for my bakes though haha!

  • Alex Groves
    June 3, 2020 at 6:44 pm

    5 stars
    Literally just done this recipe, baked it for 35mins so hoping it’s alright as did 25mins and was still not baked. Cant wait to try it later.

    Reply
  • Em
    June 3, 2020 at 1:47 pm

    Hi I have a 13” by 9” tin.. what would you suggest in regards to changing any measurements? Thank you!

    Reply
  • Millie
    June 1, 2020 at 7:26 pm

    Hi, I made these and they are amazing! Do you know what I would need to do if I wanted to have a bit of a chewy edge? Is it just leave them in for longer? Or do I need to alter how I cook them?

    Reply
    • Jane's Patisserie
      June 2, 2020 at 11:42 am

      Hey! Yes I would probably leave them in a bit longer, but you don’t want to over bake and get cakey!

  • Milly Day
    May 31, 2020 at 8:36 pm

    I am going to attempt to make your gorgeous brownies tomorrow! But I want to do Oreo brownies, because you suggest freezing mars bars would you freeze oreos too beforehand?

    Reply
    • Jane's Patisserie
      June 1, 2020 at 9:10 am

      Hey! No I wouldn’t bother freezing the oreos!

  • Maria
    May 28, 2020 at 3:21 pm

    5 stars
    Fantastic recipe! Shared with. My friends and they all love them too!

    Reply
  • Carol
    May 25, 2020 at 8:14 pm

    Hi Jane I’m crazy baking all your Blondies and Brownie recipes atm so needed new tins but could only find 8×8 or 9×12 which is what I bought as I wanted a bigger batch of these Mars Brownies. Could you kindly give me the amounts needed for this size pan pls. Thx loving all your recipes!

    Reply
    • Jane's Patisserie
      May 26, 2020 at 4:17 pm

      Hey! For a 9×12″ you want to use 1.3x the recipe, so about a third more – for an 8×8″ you’ll want to use 4/5 of a recipe! xx

  • Sophie
    May 22, 2020 at 10:25 am

    Hi Jane

    I’ve made a few of your recipes now and they are amazing! I want to make these but swap the mars bars for Rolo. Would you recommended using the same weight amount of rolos?
    Thanks

    Reply
    • Jane's Patisserie
      May 22, 2020 at 7:57 pm

      Yes I would! I would also freeze the Rolos! xx

  • sarah mccarthy
    May 18, 2020 at 3:06 pm

    Is there a difference between light brown sugar and soft light brown sugar? If so, which should I use for this recipe?

    Reply
    • Jane's Patisserie
      May 19, 2020 at 8:22 am

      For my recipes at least, light brown sugar is soft – the ones I buy just say ‘light brown sugar’!

  • Holly Haith
    May 17, 2020 at 6:41 pm

    5 stars
    Omg this brownie recipe is amazing!! I swapped the Mars for 200g of milkybar buttons and 250g of Rolos! They’re we’re amazing!!

    Reply
    • Jane's Patisserie
      May 18, 2020 at 11:19 am

      Ooh yum!!

    • ANG
      May 22, 2020 at 11:52 am

      Omg…. I want to try this…. I’ve only got mini mars bars ….. what size should the chopped pieces of mars bar be

    • Jane's Patisserie
      May 22, 2020 at 7:55 pm

      I usually cut them to about 1-2cm size pieces! x

  • Eva
    May 14, 2020 at 10:00 am

    Hi Jane,

    these look fab.. how long should you freeze the mars bars for?

    Reply
    • Jane's Patisserie
      May 14, 2020 at 1:57 pm

      I would say at least an hour, but basically it’s just till they are frozen solid!

  • Kat
    May 9, 2020 at 10:09 pm

    5 stars
    Hiya

    Can you use this recipe for Rolos too?

    Reply
    • Jane's Patisserie
      May 10, 2020 at 9:09 am

      Yes, but I would recommend freezing rolos too!

  • Kat
    May 9, 2020 at 7:59 pm

    Hiya Jane can you swap the mars bars with Rolos?

    Reply
    • Jane's Patisserie
      May 10, 2020 at 9:11 am

      Yes, but I would recommend freezing rolos too!

  • Katie Geraghty
    May 8, 2020 at 6:32 pm

    5 stars
    Thankyou, thankyou, thankyou!!
    These were easy to make and sooo delicious. Quick question: What cocoa powder do you like to use in your bakes?

    Reply
    • Jane's Patisserie
      May 9, 2020 at 8:48 am

      I personally use barry cacao powder as I buy larger bags as I bake so often!

  • Victoria
    May 4, 2020 at 2:06 pm

    5 stars
    Another incredible recipe. I’ve recommended you to everyone I know.
    It was easy simple and absolutely delicious. We had them for days after, slightly warm 😍

    Reply
  • Kath
    May 4, 2020 at 2:04 pm

    5 stars
    Hi Jane

    All of your recipes are amazing but these Mars bar brownies are definitely up there as one of my favourites, along with your fabulous Biscoff brownies. This may be an odd question, but do you think it would work combining the Mars and Biscoff recipes into one – so using the frozen Mars bars inside with Biscoff spread dolloped on top? If so, would you use light brown sugar as you do in the Mars recipe or switch to caster sugar from the Biscoff recipe? Or would I honestly just be better off making them separately?!

    Reply
    • Jane's Patisserie
      May 4, 2020 at 7:23 pm

      That sounds delicious!! I would use maybe half the mars, and half the biscoff so as not to overload them! x

    • Kath
      May 23, 2020 at 11:10 am

      Thanks Jane, I gave it a go last weekend and they taste sooo good! x

  • Kathryn Hannant
    May 3, 2020 at 9:05 pm

    5 stars
    These were so easy to make as well as being super tasty!
    I had mine warmed up slightly with some ice cream which was to die for!
    Would definitely recommend if you want to add something a little extra to your bog standard brownie.

    Reply
  • Jess
    May 2, 2020 at 4:48 pm

    Might be a silly question but how do you know when they’re done ?? I can see they’re still wobbly but I don’t want to over bake. Thanks ❤️

    Reply
    • Jane's Patisserie
      May 2, 2020 at 8:18 pm

      As annoying as it is to say, you kinda learn it! They need an ever so slight wobble in the middle, but nothing crazy. You can try a skewer, but as there’s chocolate chips and mars bar and all sorts, it probably won’t ever be fully clean! I find the best thing if you’re worried is to let them cool, and then stick them in the fridge for about an hour to help ‘set’ them!

  • Rachel Mander
    April 29, 2020 at 3:51 pm

    I was gifted some 100% cocoa which is inedible raw!
    Would it work in these brownies?
    Thanks 🙂

    Reply
    • Jane's Patisserie
      April 29, 2020 at 7:20 pm

      Yes definitely! I love using 100% cocoa powder.

  • Lianne Cook
    April 28, 2020 at 8:39 pm

    5 stars
    Hi jane would an 8 x 8 tin be ok??
    Thankyou.
    Cant wait to try it. X

    Reply
    • Jane's Patisserie
      April 28, 2020 at 9:27 pm

      An 8″ tin is typically roughly 1/5th smaller – so it should be fine, but they will obviously be deeper and take probably a bit longer to bake!

  • Alishia Mccarthy
    April 27, 2020 at 7:49 pm

    I can’t find plain flour anywhere! Is it okay to use self raising for this recipe? Can’t wait to try!

    Reply
    • Jane's Patisserie
      April 27, 2020 at 8:22 pm

      As the amount of flour is quite small, it should be fine – but they may rise and then sink down a smidge!

  • Liane
    April 25, 2020 at 5:42 pm

    Hiya, I can’t seen to get light brown sugar at the moment… would Demerara work or maybe golden caster sugar instead?! Thanks in advance x

    Reply
    • Jane's Patisserie
      April 25, 2020 at 5:43 pm

      Hiya! I would use golden caster sugar, or regular caster sugar instead!

    • Liane
      April 27, 2020 at 8:14 pm

      Thank you, they came out great!

  • Charlotte
    April 22, 2020 at 9:06 pm

    Just made these, absolutely amazing, definitely the next brownies I’ve ever made!

    Reply
  • Alisha
    March 13, 2020 at 2:11 pm

    5 stars
    Can I use stork instead of unsalted butter with brownies?
    Thanks xx

    Reply
  • Zulakha Raja
    February 27, 2020 at 1:57 pm

    5 stars
    These look amazing! When you mention dark choc – should this be cooking / non-cooking and should it be maximum darkness for maximum fudginess? I love fudgy but loathe gooey brownies 🙂

    Reply
    • Jane's Patisserie
      February 27, 2020 at 5:33 pm

      It always needs to be AT LEAST 70%, but the darker the better for a fudgey brownie yes!! x

    • Tilly
      April 22, 2020 at 5:09 pm

      5 stars
      Hi jane, these look delicious! I am making these currently, however did not read the recipe in advance and have made the mix without freezing the mars bars, is it still ok to go forth with the recipe or can I just put them in unfrozen?

    • Jane's Patisserie
      April 22, 2020 at 5:37 pm

      They might just melt a lot more than they should so not hold their form as well!

  • Naomi
    February 11, 2020 at 1:54 pm

    5 stars
    Jane, I made these at the weekend, they are so good! Thank you!

    Reply
  • Hannah
    February 9, 2020 at 9:44 am

    Hi Jane ! I made these last night they look amazing ! Very gooey in the middle I should have maybe cooked a little longer but I personally like mine gooey ! Just a storage question really are they best kept in the fridge ? Or just in airtight container at room temp ?
    Thanks so much for all your recipes baking them really helps me relax.

    Reply
    • Jane's Patisserie
      February 12, 2020 at 1:58 am

      I always say room temp so they don’t dry out!

  • Katherine Smith
    February 2, 2020 at 9:33 pm

    Hi Jane, I just tried making these and despite following the recipe completely, I have just cut them and they are still almost raw in the middle. What could I be doing wrong? I baked for 30 mins.

    Reply
    • Jane's Patisserie
      February 3, 2020 at 12:55 am

      As mentioned in the post, they can take longer in some ovens. Also, if they’re not whisked enough at the beginning, or mixed too harshly in the folding stage etc. It’s near impossible to say!

  • Giovanna
    November 26, 2019 at 10:16 pm

    5 stars
    These are fantastic!!! Easy to make and so darn good!!

    Reply
  • Gemma Hunter
    October 6, 2019 at 10:04 am

    5 stars
    Absolutely love these brownies! Made them last week for the first time for my Macmillan coffee morning and they were enjoyed by everyone! Making them again today as I didn’t get a piece..haha. Can’t wait! Totally indulgent. Many thanks Jane!

    Reply
  • Laura
    September 27, 2019 at 9:13 am

    Hi Jane,
    I’ve made these a few time and the barsbar inside just melts but I think I know why .. is it because I’m freezing the mars bar first then cutting it and it’s just basically disintegrating lol ? Should I pre cut them and then freeze them ?
    Thanks

    Reply
    • Jane's Patisserie
      September 27, 2019 at 9:56 am

      Hiya! Chances are you are cutting them too small – as you can see from the images, mine are definitely still there! I typically cut mine and freeze anyway, but it shouldn’t make a difference doing it the other way around – frozen is frozen!

  • Eve
    September 23, 2019 at 10:22 pm

    5 stars
    This is a great recipe, but despite freezing my Mars Bars overnight, they still melted entirely and left Mars-Bar-chunk-shaped holes. Not an issue for me, they still tasted absolutely delicious and the nougat stayed solid.

    Reply
    • Jane's Patisserie
      September 24, 2019 at 7:35 am

      Maybe your oven was hotter then it should have been, or you cut them too small? Try a little larger next time!

  • Kerry Evans
    September 11, 2019 at 12:52 pm

    At what stage do you put the chocolate chips in please? They’re in the ingredients but not mentioned in the method.

    Reply
    • Jane's Patisserie
      September 11, 2019 at 4:21 pm

      Oops! When you put the mars bar bits in!

  • Tia Rose Mather
    August 23, 2019 at 11:06 am

    5 stars
    Hi Jane! These look amazing and I’m going to make them tonight! How long should I freeze the mars bars for? Thanks x

    Reply
    • Jane's Patisserie
      August 23, 2019 at 11:07 am

      Just till they are solid! Depending on your freezer I guess could take a couple of hours?!

    • Kate
      May 26, 2020 at 9:04 pm

      Hi Jane,
      I’ve seen brownies to order with Snickers, peanut butter and peanut halves in it. Could this be adapted to a snickers version? If so, how please?

    • Jane's Patisserie
      May 27, 2020 at 6:39 pm

      Hey – yeah you could swap them in. Make sure to freeze the snickers first though!

  • Doreen
    August 20, 2019 at 9:34 am

    Hi Jane
    Im making these today and also making your choc fudge cake, is it ok to use 74 percent cocoa dark chocolate in both these recipes or should i use a higher percentage dark chocolate ? Many thanks Doreen

    Reply
    • Jane's Patisserie
      August 20, 2019 at 10:45 am

      I generally use 80% or so, but the minimum you should use is 70% so yours will be fine! x

  • Doreen
    August 13, 2019 at 12:30 pm

    Just taken out of oven your terry’s choc orange brownies, i did find i had to bake it extra 10 mins and although it still looked a little wobbly in the centre i think its firming up as it cools, cant wait to taste them then will definatly have a go at these mars brownies, thank you your recipes are so easy to follow xxx

    Reply
  • Deborah Bradshaw
    July 21, 2019 at 11:08 am

    Loved making these I’m a very popular nana now

    Reply
  • Emily
    July 20, 2019 at 4:05 pm

    Hi Jane,
    I’ve noticed you’ve swapped to using light brown sugar instead of caster sugar in your latest brownie recipes – is there a reason for this? Do you find light brown sugar makes better brownies? Just wondering if I should start using that instead of caster sugar for your older brownie recipes.
    Thanks!

    Reply
    • Jane's Patisserie
      July 20, 2019 at 9:27 pm

      No, it depends on the flavour of brownie. As these have mars bar’s in, which are caramel, light brown sugar works well. Caster sugar is better for others.

  • Doreen Owen
    July 20, 2019 at 1:25 pm

    5 stars
    Hi
    Cant wait to make this but can you tell me what make dark chocolate is best ?
    Thanks xx

    Reply
    • Jane's Patisserie
      July 20, 2019 at 9:26 pm

      I use Callebaut, or supermarket own really cheap stuff!

  • Fiona
    July 20, 2019 at 8:50 am

    Ingredients are on my shopping list right now!

    Reply

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