Chocolate and Cherry Wave Cake

Heat the oven to 180°C/160°C fan/gas 4. Grease and line a 30x46cm rimmed baking tray or Swiss (jelly) roll pan. Put the butter and sugar into a bowl and beat together until light and creamy. Beat in the eggs one at a time and then add the vanilla extract. Sieve together the flour, salt and bicarbonate of (baking) soda and fold into the egg mixture. Spread two thirds of the mixture evenly in the base of the prepared tin.

Stir the cocoa powder and milk into the remaining mixture. Spread the chocolate layer over the vanilla layer. Pat the cherries dry with paper towels and then scatter them over the chocolate layer. Bake in the oven for about 40 minutes until a toothpick inserted into the centre comes out clean. Leave until cold.

To make the custard put the cornflour (cornstarch) and sugar into a bowl. Heat the milk until hot but not boiling. Pour the milk onto the cornflour mixture, stirring well. Return this mixture to the pan and bring to the boil, stirring. Simmer for about 2 minutes. Add the vanilla extract and spread the thickened custard over the cake and chill in the fridge overnight.