Craving something chewy, nutty and downright delicious? These Peanut Butter Oatmeal Crumble Bars will become your new favourite baked slice recipe! Perfect for school lunchboxes or an afternoon pick-me-up!
If you’re a peanut butter lover (and let’s be honest… who isn’t?!), you need to try these chewy, golden Peanut Butter Oatmeal Crumble Bars! Made with pantry staples and bursting with nutty goodness, they’re the perfect mix of soft, sweet and crumbly.
Looking for more peanut butter recipes?
Try my peanut butter brownies (so decadent!), no bake peanut butter slice, 3 ingredient microwave peanut butter fudge or my Reese's peanut butter cookies!
Why You’ll Love This Recipe
✔ Super Easy – Just mix, press, bake, and enjoy—no fancy techniques required!
✔ Nutritious & Filling – Made with rolled oats, peanut butter, and pantry staples for a satisfying, energy-boosting snack the whole family will love.
✔ Great for Lunchboxes – These bars are kid-friendly, school-approved (just swap for a nut-free butter if needed), and don’t need refrigeration.
✔ Customisable – Add chocolate chips, nuts, or dried fruit to make them your own.
✔ Soft & Chewy Texture – A deliciously crumbly base, a smooth peanut butter layer, and a golden oat topping!
Peanut Butter Oatmeal Bars Ingredients
These oatmeal peanut butter bars come together so well with just a handful of simple ingredients:
Note: Scroll to the recipe card at the bottom for the ingredients quantities and full detailed method.
- Rolled Oats – Adds chewiness and texture (also called old-fashioned oats). You can substitute with quick oats if you prefer, however rolled oats will give you the ultimate chewy texture.
- Raw Sugar & Light Brown Sugar – The perfect combination for a golden, caramel-like flavour.
- Peanut Butter – The star ingredient! Use smooth and creamy peanut butter or crunchy peanut butter, depending on your individual preference.
Variations
🔹 Nut-Free Version: Swap peanut butter for sunflower seed butter or tahini for a school-friendly alternative.
🔹 Chocolate Peanut Butter Bars: Stir through ½ cup of regular chocolate chips or chunks of chopped dark chocolate into the crumble mixture.
🔹 Coconut & Peanut Butter Bars: Add ½ cup of shredded coconut to the base for extra chewiness.
🔹 Fruit & Nut Bars: For a healthier version, mix in dried cranberries, chia seeds, sultanas, flax seed, or chopped nuts for added texture and flavour.
How To Make Peanut Butter Oatmeal Bars
Let's make peanut butter oat bars!
Note: Scroll to the recipe card at the bottom for the ingredients quantities and full detailed method.
- Step 1: Preheat your oven to 160°C (fan-forced). Line a 20cm square cake tin with baking paper, making sure to leave some overhanging edges for easy removal later.
In a large mixing bowl, whisk together the plain flour, rolled oats, salt, and bicarbonate of soda. Stir in the raw sugar and brown sugar, ensuring everything is well combined.
- Step 2: Pour the melted butter and vanilla extract into the oat mixture, stirring until everything is evenly coated and comes together into a crumbly texture.
- Step 3: Take just over half of the crumble mixture and press it firmly into the base of your prepared tin, smoothing it out evenly with the back of a spoon.
Bake for 10-15 minutes, or until lightly golden. Remove from the oven and let it cool slightly, but keep the oven on.
- Step 4: Once the base has cooled a little, spread a layer of ½ to ¾ cup of peanut butter evenly across the surface.
- Step 5: Sprinkle the remaining crumble mixture over the peanut butter, making sure to cover it evenly.
Return to the oven and bake for 20-25 minutes or until the topping turns a lovely golden brown colour.
Expert Tips
✔ Allow the base to cool slightly before adding peanut butter. This makes it much easier to spread.
✔ Press the base firmly. This helps the slice hold together.
✔ Refrigerate before slicing. The bars will set properly and slice cleanly.
✔ If the crumble is browning too quickly, cover with foil and continue baking.
✔ Enjoy warm or cold! Serve with ice cream, custard, or cream for a dessert-style treat.
Storage & Freezing
✔ Fridge - For the best texture, store in an airtight container in the fridge for up to 1 week. Storing the slice at room temperature will make it lose its crunchy crumble on top.
✔ Freezer - Freeze in an airtight container for up to 3 months. Allow to defrost in the fridge before serving.
Peanut Butter Oatmeal Bar FAQS
While you can use quick-cooking oats if that's what you have on hand, rolled oats will provide a chewier texture.
Yes! Just swap the plain flour for gluten-free flour and ensure your oats are certified gluten-free.
Absolutely! Just remember that natural peanut butter is runnier and less sweet, so you may need to adjust the sugar slightly.
These peanut butter oatmeal crumble bars have a soft, chewy base, a smooth peanut butter layer, and a golden, crumbly topping—absolutely delicious!
More Oat Recipes You’ll Love
If you love these peanut butter oatmeal crumble bars, try these next:
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Peanut Butter Oatmeal Bars
Ingredients
- 185 g (1¼ cups) plain flour all-purpose
- 110 g (1¼ cups) rolled oats
- ½ teaspoon salt
- ½ teaspoon bi-carbonate of soda baking soda
- 100 g (½ cup) raw sugar
- 80 g (½ cup) brown sugar packed
- 170 g (¾ cup) butter melted
- 1 teaspoon vanilla extract
- ½ - ¾ cup peanut butter
Instructions
- Preheat oven to 160 degrees celsius (fan-forced).Grease and line a 20cm square cake tin with baking paper, allowing the edges to overhang.
- In a large bowl, whisk together the plain flour, rolled oats, salt and bi-carbonate of soda. Stir in the raw sugar and brown sugar and mix until smooth.
- Add the vanilla extract and melted butter to the dry ingredients. Stir mixture until well combined.If using a Thermomix: Melt the butter and vanilla extract for 3 minutes, Speed 2, 80 degrees. Add the plain flour, rolled oats, salt, bi-carbonate of soda, brown sugar and raw sugar. Mix for 20 seconds on Reverse, Speed 2. Scrape down the sides. Mix for a further 20 seconds on Reverse, Speed 2.
- Press just over half of the crumble mixture into the base of the prepared tin and use the back of a spoon to smooth the mixture into an even layer. Bake in the preheated oven for 15 minutes, until golden.Remove from oven and set aside to cool slightly (leave the oven turned on).
- Spread the peanut butter over the top of the cooked base. Use ½ cup peanut butter for a thin layer or ¾ cup for a slightly thicker layer (the more the better in my opinion!)
- Sprinkle the remaining crumble mixture over the top of the peanut butter.
- Bake in the oven for 20 - 25 minutes or until lightly golden.Remove from oven and allow to cool.
- Cover and refrigerate for at least 2 hours (preferably overnight) then take it out and cut into squares.
Notes
- Swap the peanut butter for sunflower seed butter or tahini for a nut free option.
- Add some chocolate chips or chunks of chopped dark chocolate to the crumble topping mixture.
- Add some shredded coconut, dried cranberries, sultanas or chopped nuts to the crumble topping before baking.
- All ovens are different - The slice is ready when the crumble is golden. I specify degrees celsius (fan-forced) for my recipes. If you're using a conventional oven, increase the temperature by 10-20 degrees celsius.
- If you find that your crumble is over-browning, simply add a sheet of foil loosely over the top and continue baking.
- Allow the base to cool slightly before adding the peanut butter (this will make it easier to spread).
- Refrigerate before slicing, then cut the slice using a sharp serrated knife.
- This crumble slice is delicious served cool or warmed up with a scoop of ice-cream, custard or cream.
- Store the slice in an airtight container in the fridge for up to one week.
- Freeze the slice in an airtight container for up to 3 months. Allow to defrost in the fridge before consuming.
Lucy says
My son loves this recipe!!!