Better Than Sex Cake

Instructions

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.