Better Than Sex Cake

Method

1. Heat the oven to 180C. Line the base of a 10 cm round cake tin (or a shallow 300 ml baking dish) with baking paper so the soaked cake will lift out cleanly.
2. In a small bowl, whisk together 45 g plain flour, 45 g caster sugar, 8 g cocoa powder, 0.25 tsp bicarbonate of soda and 1 pinch fine salt, breaking up any lumps of cocoa with the whisk.
3. Add 2 tsp vegetable oil, 0.5 tsp white vinegar, 0.5 tsp vanilla extract and 60 ml warm water. Whisk just until the batter is smooth and glossy — about 30 seconds — and stop as soon as no dry flour remains; the vinegar and bicarbonate start working straight away.
4. Pour the batter into the lined tin and bake on the middle shelf for 20-22 minutes, until the top springs back when pressed and a skewer inserted in the centre comes out with no wet batter on it.