In a large bowl, beat together the butter and caster sugar until the mixture is light and fluffy. Photographs by Pradeep Gaur/Mint

Add one egg at a time, with a spoonful of flour (to stop the mixture curdling), and keep beating until smooth

Repeat until you have used all the eggs, then gently fold in the remaining flour

Mix well, adding a little milk until the mixture has a “soft-dropping” consistency

Divide the cake mixture in two

To one half, add the cocoa powder, with more milk, and mix well

Put spoonfuls of the two mixtures randomly into the lined tin

Gently swirl a spoon through the mixture in the lined tin to create a marbled effect

Smooth the top of the cake mixture and bake for 45 minutes to 1 hour

Spread the icing on its surface and serve