Chocolate concrete will take you straight back to school days. This classic chocolate crunch uses just four ingredients, is quick to make and delivers a satisfyingly crisp sugar topping with a rich cocoa base. Serve warm with pink custard for a nostalgic treat or enjoy chilled by the slice.
Also popular as chocolate crunch, this simple retro recipe is deceptively good. The sugar crust gives a crisp bite that contrasts beautifully with the cocoa-rich interior. It’s the sort of bake that brings back memories and is perfect alongside a cup of tea or coffee.
Here’s why this is a must-bake
- Only four ingredients you likely already have
- Can be vegan if you use margarine instead of butter
- Ready in under 30 minutes
- Great to make with children
Chocolate concrete or chocolate crunch?
Chocolate concrete and chocolate crunch are the same thing. The name “concrete” refers to the way the cake firms up as it cools. If you cut it straight from the oven it will be a little softer; left to cool it becomes firmer and more like the classic crunchy texture. Both are lovely—serve warm with pink custard for true school-dinner nostalgia, or enjoy cold as an easy sweet snack.
Cake or biscuit?
This bake behaves more like a shortbread-style biscuit because it contains no eggs or raising agents and therefore stays flat. Swap butter for margarine to keep it vegan. Some versions include eggs and baking powder for a softer, more cake-like result, but the traditional concrete/crunch relies on a dense, crumbly texture.
Cocoa powder or drinking chocolate?
Unsweetened cocoa powder gives a deeper, truer chocolate flavor. A mid-range cocoa such as Cadbury’s Bournville works well here — no need for the very darkest, most expensive powders. You can use drinking chocolate in a pinch, but the color and intensity won’t be as pronounced.
Chocolate concrete recipe — step by step
Full measurements and a printable recipe card are provided below in the recipe section. Read through the steps before you start for the best results.
- Preheat the oven to 180°C (350°F) or 160°C (325°F) fan. Line an 8-inch (or 7-inch) square tin with baking paper and grease it or spray with cake release.
- Combine the flour, granulated sugar and unsweetened cocoa powder in a bowl. Stir well with a fork or sift the dry ingredients together to remove lumps and ensure an even color.
- Melt the butter, pour it into the dry mix and stir. Use your hands to rub the butter into the dry ingredients until you have a crumbly, wet-sand texture.
- Tip the mixture into the prepared tin and spread it evenly. Cover your hand with a sandwich bag and press down firmly, or use the back of a spoon to compact the mixture into a flat, even layer.
- Bake for 20 minutes. As soon as you remove the tin from the oven, lightly mist the hot surface with water (a spray bottle works well) and sprinkle granulated sugar over the top. Optionally add a little pink sanding sugar for a traditional school-dinner look.
- Cool on a wire rack. Slice while still a little warm if you prefer softer pieces, or wait until it’s fully cooled to get that firmer “concrete” texture. Serve alone or with warm pink custard.
Recipe notes
- Slice while slightly warm for easier cutting and a softer bite, or cool completely for a firmer, crunchier texture. Triangles are traditional, but cut any shape you prefer.
- Store slices in an airtight container at room temperature for a few days — if they last that long.
Looking for more retro school day treats?
Cake
Chocolate School Cake
Cake
School Cake (Sprinkle Vanilla Tray Bake)
Cookies & Bars
Jammie Dodger Blondies
Cookies & Bars
Homemade Jammie Dodgers
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School Days Chocolate Concrete with Pink Custard
Equipment
- 8 inch or 7 inch square brownie pan
- Cake release or non-stick spray
- Digital scales (optional but useful)
Ingredients
For the chocolate concrete
- 240 g (2 cups) plain/all-purpose flour
- 225 g (1 cup + 2 tbsp) granulated sugar
- 60 g (8 tbsp) unsweetened cocoa powder
- 115 g (½ cup) unsalted butter or margarine
Topping
- 2 tbsp granulated sugar
- 1 tbsp pink sanding sugar (optional, for appearance)
Pink custard
- 600 ml (2½ cups) whole milk
- 1 packet strawberry blancmange powder (Pearce Duff’s for authenticity)
- 3 tbsp caster sugar, or to taste
Instructions
Chocolate concrete
- Preheat the oven to 180°C (350°F) or 160°C (325°F) fan. Line and grease a square tin.
- Add the flour, sugar and cocoa powder to a mixing bowl and stir until lump-free and evenly colored.
- Melt the butter, pour it into the bowl and mix. Rub the butter into the dry ingredients with your fingers until the texture resembles wet sand.
- Transfer the mix to the prepared tin and press down firmly into an even layer using a bag-covered hand or the back of a spoon.
- Bake for 20 minutes. Remove from oven, mist with a little water and sprinkle with the granulated sugar and optional pink sanding sugar.
- Slice while slightly warm if you prefer softer pieces, or cool completely for a firmer texture. Store in an airtight container.
Pink custard (just like school)
- Warm the milk — do not boil. Put the blancmange powder and sugar into a saucepan and add a splash of warm milk to make a smooth paste.
- Gradually add the remaining milk, stirring. Heat gently over the lowest setting, stirring constantly, until the custard starts to thicken.
- If necessary, pass the custard through a fine sieve to remove any lumps. Serve immediately to avoid a skin forming.
Nutrition
Nutritional information is approximate and will vary with ingredient brands and serving sizes.
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