Chocolate Sheet Cake

Discover your new favourite chocolate cake, perfect for birthday parties or bake sales

This American-style traybake is super-easy to make, can be prepared in advance and cuts into even portions. Decorate it however you like: top with a choice of sweets and nuts, scatter over chocolate shavings and colourful sprinkles, or use chocolate buttons to spell out a name.

SERVES 10 PREP 15 mins COOK 30 mins EASY V, un-iced only

For the chocolate sponge

185ml vegetable oil, plus extra for the tin

250g plain flour

80g cocoa powder

21/2 tsp baking powder

1 tsp bicarbonate of soda

325g light brown soft sugar

250ml buttermilk

125ml strong coffee or espresso, (can be warm, but not hot)

2 tsp vanilla extract