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Homemade Peanut Butter Flapjack Recipe
Delicious peanut butter flapjacks, a classic UK treat! Find out how to make it below with this simple yet scrumptious recipe.

These peanut butter flapjacks are my latest obsession: they are high in protein, the taste is unforgettable and they’re so hard to resist.
Not only does this recipe taste amazing, but it’s ready in 30 minutes and you only need 5 ingredients to make it.
Homemade flapjacks are very customisable as you can add different flavours to it. The addition of peanut butter adds a nutty flavour which contrasts beautifully with the sweet caramel flapjack taste.

Why You’ll Like This Recipe
- Easily customisable; you can add a variety of different ingredients.
- These peanut butter flapjacks are naturally vegan!
- It’s so easy to make, just like my other flapjack recipes.
- The texture is soft, crunchy around the edges and slightly chewy in the middle.
- You can scale the recipe to make big batches.
- Great for breakfast, lunchboxes and picnics.
If you’re looking for a snack that’s high in fibre and protein, then this peanut butter flapjacks recipe is the perfect snack for you.
It’s also a lot healthier than shop-brought snacks and you can choose to reduce the amount of sugar in this recipe.
Watch How To Make It
Peanut Butter Flapjacks Recipe Ingredients
Below are the few ingredients needed to make this recipe:
- Porridge Oats: Any brand of porridge oats is fine to use. Do not use jumbo oats, it’s a different size in comparison to porridge oats.
- Margarine: I like using Stork margarine, but you can also use either salted or unsalted butter. Using margarine is what makes this peanut butter flapjack recipe vegan.
- Golden Syrup: Golden syrup binds the dry ingredients together; it also adds a caramel flavour to the flapjacks (it’s also vegan).
- Light Brown Sugar: Provides a caramelised flavour, you can use caster sugar as an alternative.
- Peanut Butter: The star ingredient! It adds flavour and boosts the protein content in these flapjacks. Use smooth or crunchy peanut butter (I used smooth peanut butter).

What Can I Use Instead Of Golden Syrup In Flapjacks?
There are many alternatives you can use in replacement of golden syrup. If they don’t sell it where you live or you’ve simply run out, you can still make this recipe using the options below:
I’ve listed a few substitutes, but you can get the full list in this golden syrup alternatives post.
- Honey
- Maple Syrup
- Light Corn Syrup
- Dark Corn Syrup
How To Make Peanut Butter Flapjacks
Below is a step-by-step guide on how to make peanut butter flapjacks. Full recipe instructions are on the recipe card:
Step One:


Preheat your oven to 180°C (160°C Fan, gas mark 4) and line a baking tin with parchment paper.
Add butter, peanut butter, golden syrup and light brown sugar to a large mixing bowl and melt in the microwave on a medium heat.
Every 10 to 15 seconds stop the microwave and give the mixture a stir. Repeat this until the mixture has fully melted.
Step Two:


Add porridge oats to the melted mixture and mix together until thoroughly combined. Make sure all the oats are generously coated.
TIP: If you see spots of white oats in your flapjack mixture, then it hasn’t been mixed thoroughly enough. It should take on the golden-brown colour of the melted syrup when mixed thoroughly.
Step Three:

Pour the flapjack mixture into the lined baking tin and spread it evenly into all four corners. With the back of a spoon, press the flapjack mixture down.
Step Four:

Bake in the oven for 20 minutes or until the edges have turned golden brown. Once baked, leave the flapjack to cool down before cutting it into slices.
Peanut Butter Flapjack Decoration Ideas
There are many ways that you can decorate these peanut butter flapjacks but of course you can leave them plain if you want too.
My favourite decoration idea is to drizzle melted chocolate on top, it’s quite simple but it does look good. You can use white chocolate, dark chocolate or milk chocolate; if you don’t want to use chocolate you can use peanut butter (like in my photos).
You can also sprinkle chopped peanuts or chocolate covered peanuts on top of the chocolate.
You don’t have to cut the flapjacks into squares, you can cut it into rectangles and dip one end in melted chocolate or peanut butter.

Recipe Variations
Dried Fruit And Seeds: Add extra flavour by adding sunflower seeds or dried fruit like raisins, apricot, bananas and apples. Not only will it increase the flavour, but it will also add more texture too.
Add Peanuts: Boost the peanut butter flavour by adding peanuts (or chocolate peanuts).
No Sugar: If you want to make healthy peanut butter flapjacks, then you can make this recipe sugar free! Remove the sugar and replace golden syrup with honey.
Use Honey: If you don’t have golden syrup, you can use honey instead, it’s a great golden syrup substitute.
Use A Different Nut Butter: Don’t want to use peanut butter? No problem! You can use other nut butters like almond butter or cashew butter.
Make A Peanut Butter And Jelly Flapjack: Add two to three tablespoons of strawberry (or raspberry) jam to the flapjack mixture.
Why Are My Flapjacks Crunchy?
If your flapjacks are hard and crunchy, then it’s likely that the butter, golden syrup and sugar mixture were overheated when melted. When melting these ingredients together, melt on a medium heat instead of using a high temperature.
It could also be that the flapjacks were left in the oven for too long or were baked at a high temperature. Bake the flapjacks at 180°C (160°C Fan, gas mark 4) for 20 minutes to avoid crunchy flapjacks.

My Top Tips
The longer you bake the flapjacks in the oven the crunchier they become, so if you want chewy flapjacks bake it for 20 minutes. For a crunchier peanut butter flapjack texture, bake it for 35 to 40 minutes or until you have reached your desired texture.
Allow the flapjacks to cool down first before you cut it into slices. Fresh out of the oven they are quite soft but they harden as they cool. You can score the flapjacks whilst warm then slice them when cold, this is a great tip to prevent the flapjacks from breaking.
A golden-brown flapjack is a good indicator that the flapjacks are ready to come out of the oven.
For extra flavour add vanilla extract, it’s an optional ingredient but it does add a nice contrasting taste to the salty flavour from the peanut butter.

How To Store & Freeze Peanut Butter Flapjacks
Store peanut butter flapjacks in an airtight container and keep at room temperature for up to 5 days. If you want to keep the flapjacks for a longer period, then you’re better of freezing it.
To freeze, once the flapjacks have cooled down completely, place them in a freezer-safe container and keep in the freezer for up to 3 months.
A great tip is to line each layer with parchment paper to prevent sticking, also cut the flapjacks into slices before freezing so you can easily defrost individual slices.
Equipment Needed
To make this recipe, you’re going to need the equipment below:
Baking Tin: I used a 9″ baking tin for this recipe, it creates around 16 flapjack slices. You can get more or less slices depending on how big the portions are cut. If you want chunkier flapjacks, then you can use a smaller 8″ baking tin.
Parchment Paper: Used to line the baking tin.
Mixing Bowls: You’ll need a large enough mixing bowl to mix the ingredients together.

Do Flapjacks Harden As They Cool?
Yes, they do! Flapjacks are quite soft when freshly taken out of the oven. As the flapjacks are left to cool down they harden. That’s why it’s important to cut flapjacks when they are cold as they’re less likely to break apart.
More Flapjack Recipes
If you loved this peanut butter flapjack recipe, then you’re going to love these other recipes too:
- Triple Chocolate Flapjack
- Gooey Flapjacks
- Cherry Bakewell Flapjacks
- Chocolate Chip Flapjacks
- Biscoff Flapjacks
- Lemon Flapjacks
- White Chocolate Flapjack
- Honey Flapjacks Recipe
- Banana Flapjack Recipe

Peanut Butter Flapjacks
Equipment
Ingredients
- 400 g Porridge Oats
- 250 g Margarine (Or Butter)
- 150 g Light Brown Sugar
- 150 g Peanut Butter (Crunchy Or Smooth)
- 150 g Golden Syrup
Instructions
- Preheat your oven to 180°C (160°C Fan, gas mark 4) and line a baking tin with parchment paper.
- Add butter, peanut butter, golden syrup and light brown sugar to a large mixing bowl and melt in the microwave on a medium heat.Every 10 to 15 seconds stop the microwave and give the mixture a stir. Repeat this until the mixture has fully melted.
- Add porridge oats to the melted mixture and mix together until thoroughly combined. Make sure all the oats are generously coated.
- Pour the flapjack mixture into the lined baking tin and spread it evenly into all four corners. With the back of a spoon, press the flapjack mixture down.
- Bake in the oven for 20 minutes or until the edges have turned golden brown. Once baked, leave the flapjack to cool down before cutting it into slices.
Video
Notes
Do Flapjacks Harden As They Cool?
Yes, they do! Flapjacks are quite soft when freshly taken out of the oven. As the flapjacks are left to cool down they harden. That’s why it’s important to cut flapjacks when they are cold as they’re less likely to break apart.What Can I Use Instead Of Golden Syrup In Flapjacks?
There are many alternatives you can use in replacement of golden syrup. If they don’t sell it where you live or you’ve simply run out, you can still make this recipe by using an option from my golden syrup alternatives post.Nutrition
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