Gluten-free Peanut Butter Cookie Bars Recipe (low FODMAP/dairy-free/vegan option)

Gluten-free peanut butter cookie bars recipe – crisp on the outside, soft like cookie dough in the middle and packed with Reese’s mini peanut butter cups. What more could you want?

Gluten-free peanut butter cookie bars recipe, anyone? This one is super simple and they’re even easier to make than peanut butter cookies – no rolling into balls or chilling required.

As it was my little brother’s birthday recently (that makes it sound like he’s 5 years old – add 21 years onto that!) I decided to make him a treat inspired by one of his all time faves: a peanut butter sandwich.

But we can do better than a birthday sandwich, right? Of course we can! So I merely took flavour inspo from his fave school lunch and made him something worth salivating over: my gluten-free peanut butter cookie bars.

And just as a side-note, I made these gluten-free and my brother ate them and loved them… and he can definitely eat gluten. So I think that says more than I ever could!

I mean, who wouldn’t love these? Here’s a few reasons that I know you’ll love them too:

Why bake my gluten-free peanut butter cookie bars?

• This is a one-bowl recipe – mix it all up, spoon it into your baking tin and bake. So that’s super easy and less washing up!
• They’re even easier and faster to make than cookies – no rolling into balls or chilling required.
• They’re super delicious with tons of melty peanut butter cups in every bite.
• They use Reese’s mini peanut butter cups which are gluten-free in the UK!
• Though there’s xanthan gum is in the recipe, it’s not mandatory for this one.
• Nobody would EVER know this is gluten-free – you’ll have to fight the muggles away from these!

After all, in every bite, you’re getting tons of melty Reese’s mini peanut butter cups, chocolate chips and Reese’s peanut butter chips.

Factor in that crisp on the outside, cookie dough in the middle-like texture AND the fact that the dough has peanut butter in it too… well, it’s every PB lover’s dream!

Honestly, if you’ve never tried anything like this before, then now’s the time to fix that. These are so much more than just a cookie.

They’re chunky, chewy, chocolatey, peanut buttery and one bite is never enough. Here’s everything you’ll need for this recipe, keep scrolling until you see the recipe card for the method ??

Gluten-free peanut butter cookie bars recipe: Ingredients

• 100g caster sugar
• 100g light brown sugar
• 140g butter, melted
• 150g gluten free plain flour
• 1 tbsp cornflour (cornstarch)
• 250g peanut butter, (smooth or crunchy – but ideally a more creamy peanut butter)
• 1 egg
• 1/2 tsp bicarbonate of soda
• 1/2 tsp vanilla extract
• 1/4 tsp xanthan gum, (if you don’t have it, it doesn’t matter so much for this recipe)
• 75g chocolate chips
• 50g Reeses chips (if you don’t have these add more chocolate chips)
• 90g Reeses Peanut Butter Cups (I used the mini ones)

See the frequently asked questions section for advice on how to make this low FODMAP, vegan or dairy-free too ??

So I thought I’d kick things off with a little frequently asked questions section – if you just want the recipe, then keep scrolling.

But I’ve thrown in some tips here that will be really helpful if this is your first time baking this, or you want to adapt it. So here they are!

Gluten-free peanut butter cookie bars recipe: Frequently asked questions

Can I make this recipe gluten free? Is it suitable for Coeliacs?

It is gluten free, though nobody would know just by tasting it – trust me!

Bear in mind that minimising cross-contamination is hugely important if you’re Coeliac or making this for someone who is. Here’s some tips from Coeliac UK on minimising the risk of cross contamination:

Also, make sure that all ingredients used don’t have any gluten-containing ingredients. Then make that that they also don’t have a ‘may contain’ warning for gluten, wheat, rye, barley, oats (which aren’t gf), spelt and khorasan wheat (aka Kamut).

Here’s some more info from Coeliac UK on identifying safe gluten free products.

Can I make your gluten-free peanut butter cookie bars recipe dairy free?

Yes, you can with a few simple swaps! Instead of butter, use a dairy-free baking block, like Stork hard margarine. Or, any kind of hard dairy-free alternative to butter.

Then, simply use dairy-free chocolate chips.

Of course, you’ll have to remove the Reese’s products as they both contain dairy. Instead you can happily replace these with more chocolate chips. Then the recipe will be totally dairy-free!

Can I make your gluten-free peanut butter cookie bars vegan?

Yep! If you follow the instructions above to make this recipe dairy free, then all you’ve got left to contend with is the egg.

Here’s a few ideas you can use as egg replacements, so each of these = 1 egg.

• 3 tablespoons of aquafaba – water from a can of chickpeas. Keep the chickpeas for a future dinner!
• Egg replacement powder – I’d recommend using Orgran as it’s gluten free.
• 1 tablespoon of chia/flax seeds mixed with 2 tablespoons of water and left for 10 minutes in the fridge.
• 3 tablespoons of applesauce.

I haven’t tested all of these egg alternatives so let me know how you get on in the comments below ?? 

Can I make this recipe low FODMAP?

To make this recipe low FODMAP, firstly ensure that you use lactose-free chocolate chips. Next, omit the Reese’s products for more lactose-free chocolate chips. Simple!

Is your gluten-free peanut butter cookie bars recipe nut free?

Sadly this isn’t a nut free recipe due to the peanut butter required in the cookie dough mixture. You can always make my original gluten-free cookie bars nut free though.

Where can I find Reese’s Mini Peanut Butter Cups and Reese’s chips? Are they gluten-free?

I found the Reese’s chips down the baking aisle in Asda, but I believe they also sell them in Sainsbury’s too.

You can find Reese’s mini peanut butter cups in any supermarket with all of the chocolate.

At the time of writing, both products are gluten-free (no gluten-containing ingredients and no ‘may contain’ warning) but please check the ingredients for yourself as you never know when things might change.

Can I make your gluten-free peanut butter cookie bars in a food processor or standing mixer?

I’d recommend avoiding a food processor as it can break up/blend the chocolate chips and Reese’s peanut butter cups too much.

A standing mixer or an electric mixer works perfectly.

Can I make your gluten-free peanut butter cookie bars recipe by hand?

You can of course, bake this without any assistance from any appliance – just a good ol’ fashioned silicone spatula will do. Just make sure you give it a lot of welly, otherwise your mixture won’t be consistent and might not bake properly.

Do I need any special equipment to bake your gluten-free peanut butter cookie bars recipe?

As I mentioned, you can easily make this entire recipe by hand, so you certainly don’t need any crazy appliances or anything like that.

What you will need however is a 9″ square baking tin – here’s the one I use. Apart from that, you’ll just need a little baking paper too!

Does this recipe need xanthan gum?

You’ll see xanthan gum in a lot of my recipes as it’s an essential ingredient in gluten free baking.

There is a little included in this recipe, but if you can’t tolerate xanthan gum, or you don’t have any, it would be fine to omit from this recipe.

Can I make this recipe using other gluten free flours like buckwheat flour or coconut flour?

There’s a big difference between ‘gluten free plain/self-raising flour’ and a *singular* type gluten free flour. When I say ‘gluten free plain or self-raising flour’ in a recipe, I mean a BLEND of gluten free flours, not just one, singular flour.

Most gluten free flour you buy in the supermarket typically contains a blend of rice flour, potato flour, maize flour, tapioca flour AND buckwheat flour. That’s a lot of different flours!

In gluten free self-raising flour, there’s usually even a little baking powder and xanthan gum in it too which always helps. So to replace it with just one specific type of flour… that’s not going to cut it at all. Definitely go for a gluten free flour blend.

Do I need weighing scales to bake your gluten-free peanut butter cookie bars?

In short… yes, yes and yes! And I wouldn’t advise attempting any my recipes without them.

A lot of work went into fine tuning ratios and quantities and for me, baking is all about consistency and precision. I want you to make this recipe and for it to turn out EXACTLY like mine did.

For example, adding too much flour can make things dry and crumbly, whereas not adding enough sugar means it’ll lose its crisp exterior. I don’t want you to be disappointed, so please weigh your ingredients!

I’d recommending using digital cooking scales like these so you know you’re getting an accurate measurement and replicating my recipe as accurately as poss.

Can I bake your gluten-free peanut butter cookie bars recipe with less sugar / without sugar?

As always, I advise removing/lowering sugar at your own risk because sugar isn’t just for sweetness – it’s integral to the structure of your creation, once baked.

Cookies basically don’t function without sugar so I wouldn’t recommend removing it! Reduce the amount of sugar at your own risk as it will always result in a less than perfect finish.

How long can I keep your gluten-free peanut butter cookie bars for?

In an airtight container, they should last up to 4-5 days. When they start getting a little dry, they’re probably past their best.

Can I freeze your gluten-free peanut butter cookie bars?

Yep! You can freeze them for up to 2-3 months without a problem – just make sure you put it them in an airtight plastic container.

It’s probably a good idea to slice it all first so you can defrost a slice at a time.

A single slice should take around 4-5 hours to thaw at room temperature.

How can I tell when my gluten-free peanut butter cookie bars are done?

Grab a skewer and give it a poke in the centre. If it comes out clean, then it’s done! You might get a little chocolatey residue on there, but that’s ok too.

And definitely allow them to cool so they can firm up – they’ll be a lot stronger once they’ve cooled.

Can I print your gluten-free peanut butter cookie bars recipe?

Of course! Just hit the print button located on the recipe below ?? (otherwise you might end up printing this entire post which would probably make your printer go into early retirement)

Gluten-free peanut butter cookie bars recipe: Method

Ok, so here’s a printable version of my gluten-free peanut butter cookie bars recipe. Please remember to give it 5 stars if you tried it and enjoyed it as it helps people know it’s worth trying too! ⭐️ Feel free to leave your written reviews in the comments below this post.

Thanks for reading all about my gluten-free peanut butter cookie bars recipe! If you make it, I’d love to see how it turned out so don’t forget to take a snap of your creations and tag me on Instagram!

Any questions about the recipe? Please do let me know by following me on Instagram and leaving me a comment on a recent photo!

Thanks for reading,

Becky xxx

Don’t forget to pin this for later!