Step 1

Preheat the oven to 350 degrees F. Grease a ring mold 9½ inches in diameter, with 5 cup capacity.

Step 2

Put the butter, sugar, flour, baking soda, baking powder, eggs and zest of orange into a processor and blitz to a batter. Pour the orange juice, with the motor running, down the funnel of the processor to make the cake mixture lighter and smoother.

Step 3

Divide the batter between two bowls. Put the cocoa and espresso powder into a small bowl and whisk in the milk; fold this into one of the bowls of cake mixture to make it dark colored. Spoon a splodge of light-colored cake batter into the pan, and then a chocolate-colored spoonful working around the ring of the mold.

Step 4

Carry on with a second layer, but don’t worry if it is haphazard and not terribly even as this is the whole point of the marbling. Once you have used up both the batters, give the contents of the ring mold a swirl with a spatula to create the marble effect, and bake in the oven for 35 minutes or until a cake tester comes out clean. ​

Step 5

Let it sit on a cooling rack for about 10 minutes before turning out on to the rack to get completely cold.