These gluten-free flapjacks are soft, chewy and super easy to make. They're perfect if you need a coeliac-friendly sweet treat without missing out on that traditional golden syrup flavour and chewy texture!

Who doesn't love a good old British flapjack?! As delicious as they are, they are usually not suitable for those with gluten allergies. So I fixed that!
To be honest, I didn't need to make many changes, other than slightly switching up the type and amount of oats I used. Gluten-free oats naturally produce a drier texture so I cut the amount back ever so slightly and voila! A tasty gluten-free flapjack!
These are a great allergy-friendly lunchbox snack for school or work, they last for a whole week in the fridge, and defrost beautifully if you want to keep them in the freezer for longer. With just 4 simple ingredients and less than 10 minutes of prep time, even beginner bakers can make these deliciously chewy gluten-free oat bars.
As always, you can find my ingredient and equipment notes below, along with my step-by-step instructions, top tips and lots more. I hope you like the recipe and if you give it a go, please let me know how it goes. Enjoy!
Ingredients
- Butter: Salted butter is best as it helps cut through the sweetness ever-so-slightly. Avoid margarine for flapjacks, which contains a lot of water and can cause a greasy texture.
- Brown sugar: Soft, light brown sugar will give these gluten-free oat bars the best flavour. Caster sugar will also work but you'll get less of that 'caramel' flavour that brown sugar gives.
- Golden syrup: To help the oats bind together. You can swap this out for runny honey or maple syrup if you prefer.
- Gluten-free oats: Make sure to get porridge oats rather than jumbo oats, as gluten-free oats are quite dry and absorbent anyway. I used Nairn's gluten-free oats.
Equipment
- Square baking tin: An 8x8-inch tin works best for this recipe but a 9x9 will work fine too. If you'd like to use a much larger tin, adjust the recipe to fit by using my cake pan converter.
- Baking paper: Make sure to line your tin with baking paper to prevent the flapjack from sticking to it. Lining it with tin foil or spraying it with cooking spray doesn't work very well as it's a very sticky mixture!
- Large mixing bowl: For mixing everything together. You could also just pour the oats into your pan if it's large enough.
- Utensils: A wooden spoon for mixing, a tablespoon to measure the golden syrup, and a knife for scoring and cutting the flapjack. For pressing the mixture into the tin, I recommend using a small silicone spatula or the back of a metal spoon.

Aren't oats gluten-free anyway?
Yes, oats themselves are naturally gluten-free but they are almost always processed in close proximity to wheat and other gluten-containing grains, making them dangerous for those with celiac disease to consume.
If you're baking these oat bars for someone with a gluten allergy, make sure to use certified gluten-free oats to prevent any risk of cross-contamination. You will usually find them in the gluten-free section of the supermarket rather than beside the other cereals.
How to make gluten-free flapjacks step-by-step
Step 1: Start by lining an 8x8-inch with baking paper and preheating your oven to 180°C. If you're using the fan setting on your oven, set it to 160°C instead.
Step 2: Pour 300g of gluten-free oats into a large bowl. Set aside.
Step 3: Next, add 150g of butter to a saucepan along with 120g of soft light brown sugar and 2 tablespoons of golden syrup. Place the saucepan over low heat on the stove and stir gently until the sugar has dissolved and the butter has fully melted.
Step 4: Pour the mixture into the bowl with the oats and mix well. Make sure there's no wet mixture stuck to the bottom of the bowl, and that there are no dry patches of oats.

Step 5: Transfer the oaty mixture to your lined tin and press it down firmly. Then bake for 18-20 minutes, until it's golden brown around the edges.


Step 6: Let the flapjack cool for 5 minutes, then use a sharp knife to score your slices out. This means to gently press down to mark the lines without cutting fully. It will help make your flapjack slices cleaner later.
Step 7: Let the flapjack cool at room temperature, then cut it into slices and enjoy! I usually cut mine into 9 squares then half them into 18 triangles, but you can cut out 16 squares if you prefer.
Top tips
- I recommend using only porridge oats for this recipe rather than the mix of jumbo and porridge oats that I use in some of my other recipes. Gluten-free oats absorb more moisture than regular oats, so adding jumbo oats would make the mixture too dry.
- Pack the mixture down firmly in the tin. This will help prevent syrup from pooling at the bottom.
- For an extra chewy texture, pop the flapjacks in the fridge for a few hours before you cut them.
FAQs
Yes! If you're baking for someone with a gluten allergy, it's very important that you use gluten-free oats to prevent cross-contamination risk.
You sure can! All you need to do is swap out the butter for a dairy-free alternative. Check out my vegan flapjack recipe for tips!
These will last for around 1 week, depending on how you store them. They can be stored at room temperature but will last slightly longer in the fridge. I recommend putting them into an airtight container or wrapping them tightly with tinfoil.
Yes, these gluten-free oat bars are the perfect sweet treat for freezing! They'll freeze well for about 3 months and can be defrosted at room temperature. Check out my post on freezing flapjacks for more information.
Yes, there are a whole bunch of gluten-free mix-ins you can add to your flapjack mixture such as nuts, seeds and chocolate chips. Check out my full list of flapjack flavour ideas.

More flapjack ideas
- White chocolate flapjacks
- Nutella flapjacks
- Raisin flapjacks
- Peanut butter flapjacks
- Cranberry flapjacks
I hope you like my gluten-free flapjacks! Make sure to leave a comment and rating below if you give these a go. Happy baking!
Gluten-Free Flapjacks
Ingredients
- 150 g Butter
- 120 g Soft light brown sugar
- 2 Tablespoons Golden syrup
- 300 g Gluten-free porridge oats
Instructions
- Preheat your oven to 180℃ (160℃ for fan ovens). Line an 8x8 tin with baking paper.
- Melt the butter, sugar and golden syrup over low heat on the stove. Once the sugar has dissolved, remove the pan from the heat and leave to cool for a minute.
- Add the oats to a large bowl with the wet mixture. Mix until well combined.
- Press the mixture firmly into your tin and bake for around 18-20 minutes. It will look a bit wobbly in the middle at first but will firm up as it cools.
- Leave it to cool for 5 minutes then lightly score out your slices with a knife, without cutting all the way down. This will make it easier to cut clean slices later.
- Let the flapjack cool at room temperature, then cut it into slices and enjoy!
Notes
- Store in an airtight container for up to 1 week.

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