Retro chocolate sponge pudding with chocolate custard

Heat the oven to 180C/160C fan/gas 4 and line a 20 x 20cm cake tin with baking parchment. Beat the butter, sugar and a pinch of salt together in a large bowl using an electric whisk for 5 mins until light and fluffy. Add the eggs, one at a time, beating between each addition until incorporated and the mixture is a mousse-like consistency.

Sieve the flour, baking powder and cocoa over the wet ingredients, then tip in the milk and fold everything together with a spatula until there are no floury streaks remaining.

Scrape the mixture into the prepared tin and level the surface with the spatula. Bake for 40 mins, then check the sponge is cooked by inserting a skewer into the centre. If it comes out with any sticky cake mixture attached, return the sponge to the oven for another 5-10 mins and check again. Leave to cool slightly in the tin. To freeze, leave to cool completely, then wrap well and freeze for up to two months. Defrost at room temperature, then reheat as stated in the tip below.

Meanwhile, make the custard. Heat the cream and milk in a heavy-based saucepan over a medium heat – don’t let it boil. Combine the cornflour, sugar and cocoa in a large bowl, then whisk in the eggs and yolks, one at a time, until you have a smooth paste. When the cream mixture is hot and steaming, pour a splash into the cocoa paste to loosen it, then tip this back into the cream mixture. Reduce the heat to medium-low and cook, stirring continuously until the custard is thick enough to coat the back of a spoon – you should be able to draw a line through the custard on the back of the spoon using your fingertip. Remove from the heat and sieve the custard into a jug to remove any lumps. Cover the surface with a circle of baking parchment to prevent a skin forming. Cut the warm sponge into squares and serve with the custard for pouring over.