Heat the oven to 180C/160C fan/gas 4. Butter a 20cm square baking tin and line with two criss-crossed, overlapping strips of baking parchment (this will help you remove the traybake later). Put the strawberries in a food processor or mini chopper and blitz to a purée. Tip into a small saucepan and simmer for 3 mins until slightly reduced. Pour into a bowl and leave to cool.

Beat the butter and sugar together in a bowl using an electric whisk (or do this in a stand mixer) for 4-5 mins until light and fluffy. Gradually beat in the eggs, one at a time, followed by the vanilla extract. Mix in the flour and baking powder.

Divide the cake batter between three bowls, weighing for accuracy, if you like. Mix the cocoa and 2 tbsp milk into the first bowl until smooth and combined. Mix the cooled strawberry purée and a drop of pink food colouring into the second bowl, and stir the remaining milk into the last bowl.

Drop alternating spoonfuls of the three batters into the prepared tin until all three have been used up (an ice cream scoop is useful for this). Try not to mix the colours together, but spread each blob out slightly using the back of the spoon. It’s easiest to use three separate spoons to prevent colours mixing, or rinse the spoon before moving to a different coloured batter.

Bake for 30-35 mins until a skewer inserted into the middle comes out clean. Leave to cool in the tin for 15 mins, then transfer to a cooling rack to cool completely. Once cool, will keep covered in the fridge for up to three days. Next, make the topping. Whisk the cream and icing sugar together to soft peaks – it should be thick and spreadable. Spoon the topping into a piping bag fitted with a star nozzle, if you like. Or, you can spoon on the topping.

Cut the cooled sponge into 16 even squares, then pipe or spoon a dollop of the topping over each. Decorate each square with a chocolate flake before serving.