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Gooey chocolate chip cookie, gooey vanilla marshmallow, make THE most delicious s’mores cookie bars ever!

S’mores cookie bars

Ohhh so like.. yeah. Cookie bars happened again! I honestly couldn’t resist. I’ve actually baked these beauties several times, getting them slightly more perfect each time. I tried these in quite a few different ways, and honestly, this one stuck.


How could you not love marshmallow and cookies together?! If you like s’mores then you will love these. Honestly… biscuit, marshmallow, and chocolate together is heaven. You can also try these guys warmed a little for ultimate s’mores experience! 

So imagine a gooey, chocolatey cookie together with gooey marshmallow. MY IDEA OF HEAVEN!! These would suit being more towards Halloween and bonfire night, but I just couldn’t resist posting them now.

Other S’mores recipes

I recently made my no-bake s’mores cheesecake again, along with my s’mores cake for a party and everyone said how good a cookie version would be… so I knew I should finally post this recipe!

Cookie bars

I went for my usual cookie bar style recipe, as I have also used in my Mini Egg cookie bars and Rolo cookie bars. The baking time is somewhere in the middle of these two recipes.


It’s hard to explain sometimes, but the marshmallow fluff makes the cookies gooier, and stops them drying out like the Rolo cookie bars do. The Mini Egg cookie bars can often dry out a lot more as there isn’t anything in there to keep them very gooey, so the marshmallow fluff is a dream.


I love anything s’mores as I have said, but these are just DELIGHTFUL. You need to split the cookie dough into two sections… two thirds and one third.It can be a little bit faffy, but you need to press down the first lot of cookie dough so its even (often easier to use your hands) and then spread the marshmallow fluff on top.

The problem is, marshmallow fluff is so sticky, its easier to microwave it for 20 seconds so its spreadable! Then comes the problem of putting the next third of cookie dough on.



You can use any chocolate in the cookie bars, I just thought dark chocolate would be a great fit for this recipe! I wouldn’t recommend using actual marshmallows for these though as they will just boil and disappear – nobody wants to look forward to these and them see no marshmallow goodness as the end of it!

I rolled mine out onto some clingfilm, so that I could turn the layer onto the marshmallow fluff evenly! It’s awkward, but SO WORTH IT. If in doubt, blob bits of cookie dough all over the marshmallow fluff. Enjoy!

S'mores Cookie Bars

Gooey chocolate chip cookie, gooey vanilla marshmallow, make THE most delicious s'mores cookie bars ever!
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Category: Dessert
Type: Cookie Bars
Prep Time: 10 minutes
Cook Time: 20 minutes
Total Time: 30 minutes
Servings: 16 Pieces
Author: Jane's Patisserie


  • 275 g plain flour
  • 1 tsp bicarbonate of soda
  • 1/2 tsp salt
  • 1 tbsp cornflour
  • 115 g unsalted butter
  • 100 g granulated sugar
  • 100 g light brown sugar
  • 1 medium egg
  • 1/2 tsp Vanilla Extract
  • 300 g milk/dark chocolate
  • 1x tub marshmallow fluff


  • Preheat your oven to 190C/170C Fan and line a 9x9inch square tin with parchment paper, and leave to the side for now.
  • Whisk/Mix the plain flour, bicarbonate, salt and cornflour together so its evenly distributed – leave to the side.
  • In a larger bowl, melt the butter. Add in the two sugars, and whisk for about 2 minutes so the sugar starts to dissolve and the mixture is smooth. Add in the egg and the vanilla, and whisk again briefly until smooth. (I used an electric whisk)
  • Add in the dry Ingredients, and mix until a cookie dough is formed. Add in the chocolate chips and mix with a spatula until they’re spread through the cookie dough evenly.
  • Press two thirds of the the mixture into the bottom of the tin. Microwave the marshmallow fluff for 20-30 seconds and spread over the cookie dough.
  • Spread/cover the marshmallow fluff layer in the other third of the cookie dough. It might be hard to spread it, so I rolled it out onto some cling film, and then turned it onto the marshmallow layer to make it even. Bake the traybake in the oven for 20-25 minutes, until the top of the cookie bake looks ‘dry’!
  • Leave the cookie bake to cool for about 10 minutes, then leave to cool fully on a wire rack. Cut the bake into 4×4 for decent sizes, or 5×5 for smaller ones! Enjoy!


  • If you try to use actual marshmallows, they will boil and basically disappear into the cookie bars. Marshmallow fluff is usually found in the supermarkets near the Nutellas and jams etc, and its quite commonly available!
  • These delicious beings will last in an airtight container for up to 4 days, but honestly, they’ll be eaten before then.
  • You can use whatever chocolate you want in the middle – but I used dark chocolate chips. Milk or white work well, or even a flavoured chocolate!
  • Try microwaving them when they’ve cooled if you want a gooey cookie, or even add a scoop of ice cream!
  • This post was not inspired by anyone in particular – but I took inspiration from photos on Pinterest/Instagram and just has a go at it!

Find my other recipes on my Recipes Page!

You can find me on:

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.


  1. Hazel on December 7, 2023 at 10:15 pm

    Could I make the cookie dough in advance and freeze it and then make them up with the fluff and bake them at a later date? Would like to make these for over Christmas
    and I’m trying to think how much prep I can get done in advance!

  2. Christine on October 24, 2023 at 9:49 am

    Can these be frozen. I know cookie freeze well but unsure of the fluff. Thanks

  3. Jane on May 6, 2023 at 4:05 pm

    Tried this recipe just now.. Looks lovely
    I used peanut butter chips
    Thank you Jane x

  4. Nicola on January 18, 2023 at 8:27 pm

    Hey Jane,

    Reckon if you freeze mini marshmallows before putting it into the mixture, it’ll stop it from melting?

    • Jane's Patisserie on January 30, 2023 at 11:19 am

      Hiya! Sadly I don’t think so, though it is always worth a try! Enjoy! x

  5. Beth on October 20, 2022 at 11:51 am

    3 stars
    I followed the recipe to a t and ended up with a really liquid-y dough. I had to add more flour to do anything with it and ended up with more of a dry cake than a cookie. Really disappointed.

    • Jane's Patisserie on October 21, 2022 at 10:56 am

      Hiya! Unfortunately I think something may have been measured incorrectly – I have never experienced this with a cookie bar recipe! So sorry this happened! x

  6. Claire S on October 19, 2022 at 11:05 am

    Hi Jane these look incredible!! Would it work to put a layer on just marshmallows in the middle, I have tons in the cupboard?

    • Jane's Patisserie on October 21, 2022 at 10:53 am

      Hiya! Sadly I don’t think this would work – they tend to dissolve into basically nothing! Hope this helps! x

  7. Sam Williams on October 12, 2022 at 2:36 pm

    I have tried getting the fluff in every supermarket but cannot find any anywhere are you able to advise me which store you found sone please thanks

    • Jane's Patisserie on October 13, 2022 at 3:26 pm

      Hiya! I usually just order on Amazon, hope this helps! x

    • Aimee on October 21, 2022 at 9:20 am

      I found it in sainsburys on an end isle….where a their American sweets are…hope that helps

  8. Helen on September 10, 2022 at 5:27 pm

    5 stars
    Amazing recipe, my boyfriend asks me almost on a daily basis when I’m next making them so I’ve stocked up on marshmallow fluff for the foreseeable! They are absolutely delightful!

  9. olivia on February 27, 2022 at 11:47 am

    also, how would i adjust the baking time for using a 7×7 tin instead?

  10. olivia on February 27, 2022 at 11:39 am

    hiya jane! does the marshmallow fluff need to be microwaved? as these look relish and i’d love to make them, however do not own a microwave x

  11. Emily on June 30, 2021 at 2:31 pm

    I’ve made these serval times now and they are delicious and always a hit! Please please pleeeeeeease can you do a s’mores nyc cookie recipe!

    • Jane's Patisserie on July 2, 2021 at 9:38 am

      Ahh yayyy this makes me so happy! I will add it to the list!x

    • Jess D on February 23, 2022 at 9:53 am

      5 stars
      Oh my goodness, these are so great! I’m not a fan of marshmallows unless blackened over a fire, so thought we’d give your recipe with marshmallow fluff a try. So so happy with the result! Thank you Jane!

  12. Lo on May 26, 2021 at 11:25 am

    Is it possible to not use the marshmallow fluff and just make regular cookie bars or do you have a regular recipe to use?

    • Jane's Patisserie on May 28, 2021 at 10:17 am

      Hey! Yes you can, the base recipe is the same as all my other cookie bars so it might be better to just follow something like my mini egg one xx

  13. Sal on May 23, 2021 at 6:24 pm

    Hi Jane!! I’d love to make these as cookies, is there any way it would still work??

    • Lori on September 19, 2022 at 11:41 pm

      Did you try it as I’m also thinking the same.

  14. Charlotte on March 12, 2021 at 10:05 am

    Jane could you use homemade marshmallow fluff instead do you think? Or would it dissolve like marshmallows?

  15. Jade Staples on January 10, 2021 at 5:32 pm

    Hey Jane,
    I’m trying to do the S’more cookie bars but I can’t find marshmallow fluff anywhere.. I’ve been Morrisons and tesco neither have it.. Is there anything else? X

    • Jane's Patisserie on January 11, 2021 at 8:51 pm

      I’ve bought it recently in Sainsburys, but that’s all relative to your location as stock will vary. x

    • Aimee Tulloch on February 6, 2021 at 7:21 pm

      Hi Jade, it used to he really easy to get but I couldn’t get it anywhere. Ended up ordering off Amazon. Aimee x

  16. Sarah on January 7, 2021 at 8:58 pm

    If I made these in a 8in round how much less ingredients would I need

    • Jane's Patisserie on January 8, 2021 at 5:56 pm

      Stick to one egg, but reduce the rest by about 1/5 – or, bake it for longer x

  17. Apolline on November 5, 2020 at 5:24 pm

    5 stars
    Hello Jane! can I do these with your NYC triple chocolate cookies dough? Thanks!

    • Jane's Patisserie on November 5, 2020 at 5:48 pm

      Yeah it should work great!!

    • Apolline on November 5, 2020 at 7:13 pm

      5 stars
      Ok thank you! Will the bake time be the same, 25 minutes, (because the NYC cookies bake for 12 minutes)? And will they still be nice and soft 🙂 ? Thank you!

    • Jane's Patisserie on November 6, 2020 at 3:12 pm

      Yeah about 20-25 minutes! And it should be as long as it’s not over-baked!

  18. cieran on October 24, 2020 at 1:39 pm

    hey jane,
    doing another of your recipes, we’ve done about 7 now, 2 have let us down but the other 5 were fab.

  19. Gillian on May 26, 2020 at 1:30 pm

    What size in grams is the tub of marshmallow fluff please?

  20. Drew on September 8, 2019 at 12:45 pm

    Are you able to make these in a rectangular tray rather than a square one? My square one has disappeared

    • Jane's Patisserie on September 8, 2019 at 4:42 pm

      Changing the tin will change the baking time, so keep an eye on it. The volume of a differently shaped tin can also be drastically different!

  21. Annie on April 4, 2019 at 3:55 pm

    Can I make these and freeze them??

    • Jane's Patisserie on April 4, 2019 at 9:36 pm

      I’ve never frozen these particular ones, but I believe you can! Most cookies you can, the only bit I was unsure of was the marshmallow fluff factor!

    • Christine on October 24, 2023 at 9:48 am

      Did you end up freezing them… how did they turn out

  22. Julie H on July 16, 2018 at 9:04 am

    5 stars
    I made these for work, they had all gone by 11o/c! Everyone loved them, including someone who doesn’t like marshmallow. They weren’t as firm as yours, but I’m putting that down to the hot weather. Making my second batch tonight for my daughters work 😍

  23. Louise on November 14, 2017 at 11:44 pm

    Hi Jane,
    These look delicious! Have just ordered some Marshmallow Fluff and am going to make them next week!
    Please can I just ask how you got your bars to look like in the pictures if you rolled out the top layer of cookie dough and placed it on top? You can see the Fluff on top of the bars in your pictures? Or did you blob the Fluff on top? Sorry if it’s a silly question, just want to make sure I do them perfectly x

    • Jane's Patisserie on November 15, 2017 at 9:18 pm

      The layer of cookie dough on top is quite thin, and the marshmallow naturally breaks through in weaker areas. It doesn’t need to be perfect.

    • Louise on November 15, 2017 at 9:59 pm

      Great, thank you!

  24. Sarah Beevers on November 8, 2017 at 10:38 am

    Hi there – I’ve not been able to source Marshmallow fluff too easily – has anyone tried this simply with marshmallows in their place?

    • Jane's Patisserie on November 8, 2017 at 6:21 pm

      Whereabouts are you from? As noted in the tips and ideas section on the post, actual marshmallows will just dissolve and cause the traybake to not bake so well.

    • Sarah Beevers on November 8, 2017 at 7:53 pm

      I’m from Scotland!

  25. Carolyn on September 25, 2017 at 9:35 pm

    These look amazing Jane! I’m excited to try the recipe for myself!

    Carolyn x
    Faithfully Carolyn

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