This is the classic school dinner chocolate concrete. With only 4 ingredients, it’s crumbly with the crunch you know and love. A perfect retro treat, especially when topped with pink custard!

This post is sponsored by Ninja Australia.
Why We Love This
This is the perfect recipe to have up your sleeve when you need a quick, cheap and tasty dessert. With only four ingredients guaranteed to already be around the house, there’s no reason you can’t whip this up in 25 minutes.
Batch cook by doubling or tripling the recipe so you can either feed a crowd, or cut it up and freeze in portions for when you need a sweet treat the most.

What is Chocolate Concrete?
Chocolate concrete (also referred to as chocolate cement or chocolate crunch) was a classic dessert served at school dinners in England back in the 1970’s and 1980’s. Now it’s usually cooked at home for those wanting to reminisce and make the nostalgic treat for their family or you’ll find it in some bakeries or markets, depending on where you are.
Using only simple ingredients, this cheap dessert is like a cake, biscuit and brownie all rolled into one. Often cut into squares, it’s great in winter when it’s served warm with custard slathered over the top.
For more amazing nostalgic treats, check out our weetbix slice, Aussie crunch or chesters squares!
What You’ll Need
Only four classic baking ingredients required today!
- All Purpose Flour – Good old plain, all purpose flour is perfect for this recipe. Bread flour also works well. Avoid using self raising flour as this will give you a lighter, cake-like result and not the concrete you’re looking for!
- Butter – Salted butter works well for this recipe, but you can also swap out for oil or vegan butter.
- Sugar – Regular caster sugar or granulated sugar is best. Sub with brown sugar for a deeper flavour and less sweetness.
- Cocoa Powder – Make sure to use 100% unsweetened cocoa powder. If using a hot chocolate mix or Milo, up the amount to 50g / 1.75oz or around 7 tbsp.

How to make Chocolate Concrete:






- Pre-heat the oven to 180°C / 360°F. Add the all purpose flour, cocoa and sugar into a large mixing bowl and combine using a whisk or spoon.
- Melt the butter in 10-15 second bursts in the microwave until melted. Pour into the flour mix and roughly combine.
- Use your hands to really work the butter through the flour, breaking down any clumps. The mix will become crumbly like potting soil.
- Pour into a square 8 in / 19 cm cake tin lined with baking paper. Press down firmly with your hands or the back of a spoon until flat and compact. Make sure to press the edges as well to avoid crumbling after baking.
- Optional: Brush with water, then sprinkle a little extra sugar (1-2 tsp) over the top for an extra crispy crust.
- Pop in the oven and bake for 20 minutes. Remove and pull out of the pan using the baking paper. Slice into squares and serve hot with custard.
How to make in Ninja Foodi Max Multi Cooker




- Skip “pre-heat oven” and follow the steps for the conventional method above, up to Step 3. Pour cake mix into a round 8 in / 19 cm cake tin lined with baking paper. Press down firmly with your hands of back of a spoon until flat and compact. Make sure to press the edges as well to avoid crumbling after baking.
- Optional: Brush with water, then sprinkle a little extra sugar (1-2 tsp) over the top for an extra crispy crust.
- Place tin onto the Ninja Foodi rack, and fold up the handles.
- Using the rack handles, place the cake tin into the Ninja Foodi Max Multi Cooker and close the air fry lid.
- Turn the Ninja Foodi on and select Bake / Roast. Set the temperature to 175°C / 350°F and time to 20 minutes. Press start.
- Once cooked, use oven mitts on the rack handles to remove from the multi cooker. Next, take the cake out of the tin using the baking paper, cut into slices and serve immediately while hot with custard.

How to make Pink Custard:


- Pour strawberry milk into a medium mixing bowl. Add instant custard powder and whisk together.
- Add 3-6 drops of red food colouring for extra pink colour custard.
- Cook custard according to packet directions.
- Serve cold or hot over chocolate concrete cake.
Wandercook’s Tips
- Storage – Pop in an airtight container and store at room temperature for a few days, or freeze. When ready to eat from frozen, allow to thaw then heat in the microwave for 20-30 seconds to soften.
- Crispy Crust – Brushing the top with water and sprinkling with sugar gives the final cake an extra crispy crust.
- Hard or soft – If you like soft chocolate concrete, serve it immediately while hot. Otherwise, allow it to cool and harden.
FAQs
Popular options are pink custard (strawberry), green custard (mint), chocolate or just plain custard.
100% unsweetened Dutch cocoa is perfect for this recipe. It adds a rich chocolate flavour without adding in extra sugar.
Variations
- Add extras – pop in a 1/4 cup of raisins or chocolate chips for a sweet twist.
- For more flavour – Add a teaspoon of vanilla essence into melted butter.
- Make it a cake – Add an egg and use self raising flour to transform it into a chocolate cake.
- Small tins – Use smaller tins (less than 19cm / 8 in) for a chunkier slice.

Try these delicious homemade treats next:




★ Did you make this recipe? Please leave a comment and a star rating below!
Equipment
- 8 Inch Square or Round Cake Tin
Ingredients
- 1 ¾ cups plain flour / all purpose flour 200 g / 7 oz
- ¾ cup caster sugar / superfine sugar or granulated white sugar, 130 g / 5 oz
- 4 tbsp cocoa 100% Dutch unsweetened, 30 g / 1 oz
- 100 g butter 3.5 oz
Optional – For the Pink Custard
- 600 ml strawberry milk 20 fl oz
- 75 g instant custard powder 2.6 oz
- 6 drops red food dye
Instructions
How to make in Conventional Oven
- Pre-heat the oven to 180°C / 360°F. Add the all purpose flour, cocoa and sugar into a large mixing bowl and combine using a whisk or spoon.1 ¾ cups plain flour / all purpose flour, 4 tbsp cocoa, ¾ cup caster sugar / superfine sugar
- Melt the butter in 10-15 second bursts in the microwave until melted. Pour into the flour mix and roughly combine.100 g butter
- Use your hands to really work the butter through the flour, breaking down any clumps. The mix will become crumbly like potting soil.
- Pour into a square 8 in / 19 cm cake tin lined with baking paper. Press down firmly with your hands or the back of a spoon until flat and compact. Make sure to press the edges as well to avoid crumbling after baking.
- Optional: Brush with water, then sprinkle a little extra sugar (1-2 tsp) over the top for an extra crispy crust.
- Pop in the oven and bake for 20 minutes. Remove and pull out of the pan using the baking paper. Slice into squares and serve hot with custard.
How to make in Ninja Foodi Max Multi Cooker
- Skip "pre-heat oven" and follow the steps for the conventional method above, up to Step 3. Pour cake mix into a round 8 in / 19 cm cake tin lined with baking paper. Press down firmly with your hands of back of a spoon until flat and compact. Make sure to press the edges as well to avoid crumbling after baking.
- Optional: Brush with water, then sprinkle a little extra sugar (1-2 tsp) over the top for an extra crispy crust.
- Place tin onto the Ninja Foodi rack, and fold up the handles.
- Using the rack handles, place the cake tin into the Ninja Foodi Max Multi Cooker and close the air fry lid.
- Turn the Ninja Foodi on and select Bake / Roast. Set the temperature to 175°C / 350°F and time to 20 minutes. Press start.
- Once cooked, use oven mitts on the rack handles to remove from the multi cooker. Next, take the cake out of the tin using the baking paper, cut into slices and serve immediately while hot with custard.
Optional – For the Pink Custard
- Pour strawberry milk into a medium mixing bowl. Add instant custard powder and whisk together.600 ml strawberry milk, 75 g instant custard powder
- Add 3-6 drops of red food colouring for extra pink colour custard.6 drops red food dye
- Cook custard according to packet directions.
- Serve cold or hot over chocolate concrete cake.
Video
Recipe Notes
- Ingredient notes:
- All Purpose Flour – Good old plain, all purpose flour is perfect for this recipe. Bread flour also works well. Avoid using self raising flour as this will give you a lighter, cake-like result and not the concrete you’re looking for!
- Butter – Salted butter works well for this recipe, but you can also swap out for oil or vegan butter.
- Sugar – Regular caster sugar or granulated sugar is best. Sub with brown sugar for a deeper flavour and less sweetness.
- Cocoa Powder – Use 100% unsweetened cocoa powder. If using a hot chocolate mix or Milo, up the amount to 50g / 1.75oz or around 7 tbsp.
- Add extras – pop in a 1/4 cup of raisins or chocolate chips for a sweet twist.
For more flavour – Add a teaspoon of vanilla essence into melted butter. - Make it a cake – Add an egg and use self raising flour to transform it into a chocolate cake.
Small tins – Use smaller tins (less than 19cm / 8 in) for a chunkier slice. - Storage – Pop in an airtight container and store at room temperature for a few days, or freeze. When ready to eat from frozen, allow to thaw then heat in the microwave for 20-30 seconds to soften.
- Hard or soft – If you like soft chocolate concrete, serve it immediately while hot. Otherwise, allow it to cool and harden.
Nutrition

4 Comments
Liz
07/11/2022 at 4:40 amFirst time making chocolate concrete and turned out perfectly! Saving this recipe and website!
Wandercooks
07/11/2022 at 10:00 amYay, that’s awesome Liz! Cheers for the feedback.
Bex
08/02/2022 at 6:38 amCake recipe was perfect. Custard recipe was a giant fail. Custard came out looking like a dirty orange colour and it tasted powdery. Followed the recipe to a tee so not sure what happened. When I look at other recipes for pink custard this one is completely different so will go with a different recipe. Once again though cake recipe was perfect.
Wandercooks
09/02/2022 at 11:30 amHeya Bex! Thanks for letting us know how you went with the custard. We haven’t had it turn out powdery before – not sure if it was the type of custard powder used? Sometimes it will come out a little orange, as the custard powder is yellow and you’re mixing in the pink. Our strawberry custard is more a cheat’s version and not traditional at all. Next time, try a different brand of custard OR go the from scratch route. Hope this helps and glad you enjoyed the cake all the same. 🙂