This is a really easy birthday cake for kids of all ages. Dan Lepard shows you how to make it in a step-by-step video.
For the cake, line the base of a deep 20cm/9in cake tin with non-stick paper and preheat the oven to180C/350F/Gas 4.
Melt the butter over a low heat in a small pan, pour it into a bowl with the sugar, oil, cocoa powder and vanilla. Beat well until smooth, then whisk in the eggs followed by the milk and cream.
Sift the flour and baking powder into the butter mixture and beat until smooth, then spoon into the prepared tin and cover the top of the tin with aluminium foil.
Bake for 30 minutes, then remove the foil and bake for a further 20 minutes, or the top is springy and a skewer inserted into the middle comes out clean.
Remove the cake from the oven and set aside to cool completely.
Meanwhile make the cocoa frosting, mix the cocoa powder and icing sugar in a bowl. Melt the butter for a few seconds in the microwave, or in a small pan over a low heat. Mix the melted butter and the cream into the sugar and cocoa, and stir until smooth.
To assemble the cake, remove the cake from the tin, trim the top of the cake to make it flat, then cut the cake in half horizontally. Put the bottom half of the cake onto a serving plate and spread with the whipped cream. Top with the jam.
Spread the cocoa frosting onto the top of the cake and swirl it with a spoon, then carefully place it onto the bottom half of the cake.