September 25, 2017
S’mores Cookie Bars!
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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.
S’MORES!
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.
Marshmallow
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.
Assemble
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.
Tips!
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
Ingredients
- 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
Instructions
- 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!
Notes
- 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!
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J x
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Can these be frozen. I know cookie freeze well but unsure of the fluff. Thanks
Tried this recipe just now.. Looks lovely
I used peanut butter chips
Thank you Jane x
Hey Jane,
Reckon if you freeze mini marshmallows before putting it into the mixture, it’ll stop it from melting?
Hiya! Sadly I don’t think so, though it is always worth a try! Enjoy! x
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.
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
Hi Jane these look incredible!! Would it work to put a layer on just marshmallows in the middle, I have tons in the cupboard?
Hiya! Sadly I don’t think this would work – they tend to dissolve into basically nothing! Hope this helps! x
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
Hiya! I usually just order on Amazon, hope this helps! x
I found it in sainsburys on an end isle….where a their American sweets are…hope that helps
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!
also, how would i adjust the baking time for using a 7×7 tin instead?
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
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!
Ahh yayyy this makes me so happy! I will add it to the list!x
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!
Is it possible to not use the marshmallow fluff and just make regular cookie bars or do you have a regular recipe to use?
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
Hi Jane!! I’d love to make these as cookies, is there any way it would still work??
Did you try it as I’m also thinking the same.
Jane could you use homemade marshmallow fluff instead do you think? Or would it dissolve like marshmallows?
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
I’ve bought it recently in Sainsburys, but that’s all relative to your location as stock will vary. x
Hi Jade, it used to he really easy to get but I couldn’t get it anywhere. Ended up ordering off Amazon. Aimee x
If I made these in a 8in round how much less ingredients would I need
Stick to one egg, but reduce the rest by about 1/5 – or, bake it for longer x
Hello Jane! can I do these with your NYC triple chocolate cookies dough? Thanks!
Yeah it should work great!!
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!
Yeah about 20-25 minutes! And it should be as long as it’s not over-baked!
hey jane,
doing another of your recipes, we’ve done about 7 now, 2 have let us down but the other 5 were fab.
What size in grams is the tub of marshmallow fluff please?
I think they’re about 213g!
Are you able to make these in a rectangular tray rather than a square one? My square one has disappeared
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!
Can I make these and freeze them??
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!
Did you end up freezing them… how did they turn out
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 😍
Hahaha amazing!!
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
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.
Great, thank you!
Hi there – I’ve not been able to source Marshmallow fluff too easily – has anyone tried this simply with marshmallows in their place?
Sarah
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.
I’m from Scotland!
These look amazing Jane! I’m excited to try the recipe for myself!
Carolyn x
Faithfully Carolyn