Preheat the oven 180ºC fan. Line a 1 pound loaf tin with a non stick liner or parchment paper.

Put the butter and sugar into a big mixing bowl, using an electric hand beater, beat until pale and fluffy, or use a hand held whisk. Beat in the eggs, one at a time, then beat in the vanilla.

In a separate bowl, measure the flour and baking powder, mix well to combine. Spoon half the flour into the butter and egg mix, beat to combine. Add the remaining flour to the bowl and stir in with a spatula.

Divide the batter between 2 bowls and sieve the cocoa powder into one bowl, mix to combine.

Spoon both batters into the loaf tin, alternate so there are layers, try not to leave any space, to avoid air bubbles. Use a skewer to swirl the mix. Then drop the tin on the counter a few times to knock out any air bubbles.

Bake for 40 minutes, test with a skewer, when it comes out clean it’s baked. Leave to cool.

To decorate, melt the chocolate in a microwave, or double boiler. Dollop on the melted milk and white chocolate and swirl on top, leave to set (1 hour) then slice. I sliced mine before the chocolate set hard on top.

Storage: Keep in an air tight container for 3 days.

❄️Freeze: Slice and freeze flat in a bag for 3 months.