You will also LOVE my Chocolate School Cake!

A triangular piece of chocolate concrete dessert with pink sprinkles sits on a floral plate, surrounded by pink custard. Nearby, a small bowl of pink sprinkles and a pitcher of vibrant pink sauce rest on a pink and white cloth.

Fancy taking a trip down memory lane? Chocolate concrete – also known as chocolate crunch – doesn’t sound super appetizing but this old school recipe is as easy as it is yummy!

The crunch from the sugar topping giving way to a chocolate hit from the cocoa – just pure joy through and through. I’d say this is tied with my School Cake in nostalgia stakes.

Here’s Why This Is a Must Bake

Only FOUR ingredients you probably already have!
Vegan if you use vegan butter (margarine)
So quick – ready in under 30 minutes
Perfect for baking with your kids

flour, cocoa powder, granulated sugar and melted butter in bowls

Chocolate Concrete or Chocolate Crunch?

Chocolate crunch and chocolate concrete are one and the same. Some people like this crunchy chocolate cake served with pink custard (made using Pearce Duff’s strawberry blancmange powder for authenticity).

The chocolate crunch hardens to chocolate concrete as it cools. If you slice it warm straight out of the oven the texture will be slightly softer. I prefer just to grab a cold slice as a sweet treat – great with a cup of coffee or tea!

close on sliced chocolate crunch dusted with sugar

Cake or Biscuit?

Technically this is a type of shortbread biscuit. Since the recipe contains no eggs and no rising agents it stays pretty flat. It is also easily vegan – just use margarine instead of butter.

Some chocolate concrete recipes contain eggs and baking powder – this to me is more of a cake and softer in texture… not really concrete / crunchy.

Cocoa Powder or Chocolate Powder?

Unsweetened cocoa powder will give your crunch a deeper chocolatey flavor. But don’t go buying the best organic super-dark cocoa powder. I like using the more economical Cadbury’s Bournville Cocoa in this recipe.

You CAN use drinking chocolate powder in a pinch, but your concrete won’t look as dark and the chocolate taste won’t come through as strongly.

Chocolate Concrete Recipe Step by Step

↓ For the full ingredients and detailed method, jump to the recipe card.

Heat the oven to 180°C (350°F) or 160°C (325°F) if you are using the fan setting. Line a square tin with baking paper and grease with butter or spray with cake release.
Mix the flour, sugar and cocoa using a fork or wire whisk until lump free and uniform in color. You can also sift the dry ingredients into your bowl.

stirring flour, sugar and cocoa in a bowl

Melt the butter (in a pan or use the microwave) and pour into the bowl. Stir using a fork then use your hands to rub the butter into the dry ingredients until you have a crumbly sandy texture.

rubbing melted butter into flour, sugar and cocoa powder

Tip the mixture into your prepared tin and spread out. Place your hand inside a sandwich bag and press down hard to flatten the mixture or use the back of a spoon. It needs to be packed down into an even layer.

Chocolate crunch cake in square baking tin sprinkled with granulated sugar

Bake for 20 minutes. Remove from the oven and mist the hot chocolate concrete cake with a little water (I used a spray bottle) and sprinkle with the sugar.
Cool on a wire rack and grab a slice as a sweet treat or serve with warm pink custard for a trip down memory lane!

overhead shot of two plates with triangles of chocolate concrete with pink custard jug on the side

Recipe Notes

I like to slice the crunch cake while it is still a little warm, before it hardens into “concrete”. I cut mine into triangle shapes but you can cut into squares or whatever you like.
Store the chocolate concrete slices in an airtight container for a few days (it never lasts 10 minutes in our house).