Cornflake flapjack with Biscoff is crunchy, chewy and packed with irresistible spiced-caramel Biscoff flavour. If you enjoy a good cornflake traybake this quick & easy recipe is for you.
Love baking with cornflakes? Then don't miss my jammy cornflake slices.

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Why I Love This Recipe
- Taste: Just the right side of sweet with plenty of Biscoff undertones,
- Texture: This golden syrup cornflake traybake has alot more crunch that traditional oat flapjack.
- Unique: Flapjack with cornflakes is one twist on the classic. Biscoff in flapjack is another. This recipe combines both variations and the result is delicious.
- Quick & Easy: Have this bake in the oven in around 15 minutes.
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What is Cornflake Flapjack?
Quite simply, cornflake flapjack is an adaptation of traditional oat flapjack. In this variation, equal quantities of oats and cereal are used to create a crisp and crunchy vornflake traybake that is bound to impress.
The addition of Biscoff in this recipe for flapjack with cornflakes takes this concept a step further, adding extra flavour.
Flapjack lovers will enjoy my fruity flapjack, cherry Bakewell flapjack and cocoa flapjack recipes too.
Ingredients Notes

Cornflakes: I recommend Kelloggs Cornflakes. If your packet has already been opened make sure they rae not stale.
Oats: As with all my flapjack recipes I insist on using small rolled oats (also called porridge oats). Do not use large (jumbo) oats, sometimes called steel cut outs. They are too big and will lead to crumbly, greasy flapjack.
Butter: Proper butter gives the best flavour to these Biscoff cornflake flapjacks. If you need to swap for a non-dairy alternative use a dairy-free block butter alternative and add a ¼ teaspoon of salt.
Golden syrup: This is integral to any flapjack recipe and easy to find in most UK supermarkets. Please do not use maple syrup or honey as the flavour and consistency is not ideal for making this recipe. If you cannot find golden syrup the best alternative would be light corn syrup.
Biscoff spread: A generous helping of Biscoff spread elevates this recipe for flapjack with cornflakes massively. Use smooth or crunchy and it's fine to use a supermarket own brand. I'm rather fond of the Aldi version.
Step by Step Instructions
Full instructions and measurements are given in the printable recipe card at the end of this post.

Step 1. Put the butter, demerara sugar, Biscoff spread and golden syrup into a large, heavy-based saucepan. Place the pan over a low-moderate heat and let the ingredients melt, stirring often, until the sugar dissolves.

Step 2. Meanwhile put the Cornflakes into a bowl and crush they using your hands. Keep crushing them until they are quite fine.

Step 3. Mix the oats, flour and salt into the crushed Cornflakes.

Step 4. When the ingredients in the saucepan have melted give them a good stir until they bind into a thick, smooth sauce.

Step 5. Tip the Cornflake mixture into the saucepan and stir well until all ingredients are thoroughly combined.

Step 6. Spoon the mixture into a prepared baking tin, press it down firmly and bake for 30-35 minutes until golden on top.

Step 7. After 5 minutes score the top into 12 slices using a sharp knife but do not cut right through. Leave the flapjack to cool completely and then proceed to cut it into slices.
Expert Tips
Top Tip: Ensure you crush your Cornflakes well and use small (rolled) oats. If you do not then the dry mixture will not absorb the wet mixture sufficiently and your cornflake flapjack will be crumbly and greasy.
- Weigh ingredients accurately: Always use gram measurements and digital kitchen scales to weight your ingredients Cups are highly inaccurate.
- Use the correct-sized tin: a 20cm (8-inch) square baking tin.
- Grease & line your baking tin: Even if it is non-stick, it is much easier to remove your Cornflake traybake from the tin if it has been greased and lined.
- Flatten your flapjack: If your flapjack puffs up around the edge as it bakes simply run the back of a metal spoon over the risen areas as soon as it comes out of the oven.
Frequently Asked Questions
Golden syrup is an important ingredient in these flapjacks with cornflakes and Biscoff and I do not recommend leaving it out. Without it your flapjack will fall apart and the sweetness level will be altered. If you are unable to obtain golden syrup the best substitute would be light corn syrup. I do not recommend using maple syrup or honey as a substitute.
Flapjack falls apart if you use large (jumbo/ steel cut) oats, if the amount of dry ingredients (cornflakes, oats and flour) is too much compared to the other ingredients or if you cut it whilst it is still warm. It is imperative to use small, rolled oats, weight ingredients accurately and to wait until your flapjack has cooled completely before cutting it into slices.
If you do not crush your Cornflakes adequately your Cornflake flapjack might end up greasy. This is because they need to be crushed well in order to absorb all of the liquid ingredients properly (see the image in step 2 above). For the same reason, it is important to use small oats.
Yes, you can make these Biscoff Cornflake flapjacks more chewy. Just bake them for 5 minutes less than the time specified in the recipe card.
No, they are not. Biscoff spread contains gluten, so even if you ensure you use gluten-free Cornflakes and are certain that the oats are gluten-free, you would still need to find a gluten-free alternative to the Biscoff spread.
Note: This recipe has not been tested with gluten-free products.

Variations
Try adding some of the following to this glorious Biscoff & golden syrup cornflake traybake:
- Baking spices: Add 1-2 teaspoons of ground cinnamon, chai spice, pumpkin spice or mixed spice to the Cornflakes, oats and flour.
- Coconut: Stir 30g of dessicated coconut into the mixture for added flavour and chewiness.
- Dried fruit: A few raisins would pair well with this Biscoff Cornflake flapjack. Stir 75g into the mixture.
- Nuts: Almonds, hazelnuts and pecans all pair nicely with Biscoff. Try stirring 75g of roughly chopped nuts into your mixture for a change.
- Biscoff Drizzle: If you fancy a sweet topping then warm a couple of tablespoons of Biscoff spread up and drizzle it over the top of your Cornflake traybake.
More Cornflake Baking Recipes
I love baking with cornflakes and have several other cornflake traybakes plus a classic school dinner pudding to tempt you:
Have you made this recipe for cornflake flapjack with Biscoff? Please rate the recipe or leave a comment - I love hearing how you get along with my creations.
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📖 Recipe
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Cornflake Flapjack with Biscoff
Equipment
- 1 x 20cm (8-inch) square baking tin
Ingredients
- 180 g Butter
- 100 g Demerara sugar
- 150 g Biscoff spread smooth or crunchy
- 100 g Golden syrup
- 150 g Rolled oats small oats/ porridge oats - do not use jumbo oats or steel cut oats
- 150 g Cornflakes Must be crushed well - see step-by-step images (step 2)
- 50 g Plain flour
- ¼ teaspoon Salt
Instructions
- Preheat the oven to 160℃/ 320℉
- Grease and line the base and sides of a 20cm (8-inch) square baking tin with baking parchment
- Put the butter, demerara sugar, Biscoff spread and golden syrup into a large, heavy-based saucepan. Place the pan over a low-moderate heat and let the ingredients melt, stirring often with a wooden spoon, until the sugar dissolves and the butter melts.
- Meanwhile put the Cornflakes into a bowl and crush them using your hands. Keep crushing them until they are quite fine (see the photo in the step-by-step section). It is very important to crush the Cornflakes adequately, otherwise the melted ingredients in the saucepan will not absorb properly and your flapjack may turn out greasy.
- Mix the oats, flour and salt into the crushed Cornflakes.
- When the ingredients in the saucepan have melted give them a good stir until they bind into a thick, smooth sauce. This will take 1-2 minutes and you can use a balloon whisk if desired.
- Tip the Cornflake mixture into the saucepan and stir well until all ingredients are thoroughly combined.
- Spoon the mixture into the prepared baking tin, press it down firmly and bake for 30-35 minutes until golden on top.
- Let the baked flapjack cool for 5 minutes then score the top into 12 slices using a sharp knife but do not cut right through. Leave the flapjack to cool completely and then proceed to cut it into slices.
Notes
- Weigh ingredients accurately: Always use gram measurements and digital kitchen scales to weight your ingredients Cups are highly inaccurate.
- Ensure you crush your Cornflakes well and use small (rolled) oats: If you do not then the dry mixture will not absorb the wet mixture sufficiently and your flapjack will be crumbly and greasy.
- Use the correct-sized tin: a 20cm (8-inch) square baking tin.
- Grease & line your baking tin: Even if it is non-stick, it is much easier to remove your Cornflake traybake from the tin if it has been greased and lined.
- Flatten your flapjack: If your flapjack puffs up around the edge as it bakes simply run the back of a metal spoon over the risen areas as soon as it comes out of the oven.
- Make them chewier: To make these Biscoff Cornflake flapjacks more chewy, just bake them for 5 minutes less than the time specified in the recipe card.
Variations
Try adding some of the following to this glorious cornflake traybake:- Baking spices: Add 1-2 teaspoons of ground cinnamon, chai spice, pumpkin spice or mixed spice to the Cornflakes, oats and flour.
- Coconut: Stir 30g of dessicated coconut into the mixture for added flavour and chewiness.
- Dried fruit: A few raisins would pair well with this Biscoff Cornflake flapjack. Stir 75g into the mixture.
- Nuts: Almonds, hazelnuts and pecans all pair nicely with Biscoff. Try stirring 75g of roughly chopped nuts into your mixture for a change.
- Biscoff Drizzle: If you fancy a sweet topping then warm a couple of tablespoons of Biscoff spread up and drizzle it over the top of your Cornflake traybake.











Jane Coupland says
For anybody like me who loves baking with cornflakes I urge you to try this quick & easy recipe. It's so tasty and won't last long!