Plain flour - 250 gram
Unsalted butter (softened) - 200 gram
Caster sugar - 200 gram
Milk (full-fat) - 40 ml
Vanilla extract - ½ tea spoon
Eggs (large) - 3
Baking powder - 3 tea spoon
Cocoa powder (unsweetened) - 2 tea spoon
Icing sugar (for dusting)
- Preheat the oven 180C.
- Line a 1kg loaf tin with baking parchment.
- In a large bowl, beat the butter, 180g of the sugar and the vanilla extract together until the mixture is light and fluffy.
- Beat in the eggs, one at a time.
- Add the baking powder.
- Sift the flour over the mixture.
- Fold in with 2 tbsp of the milk.
- Spoon two-thirds of the mixture into the prepared loaf tin – it should fill the tin three-quarters of the way.
- Sift the cocoa in the remaining third of the mixture and fold in, together with the remaining milk and 20g of sugar.
- Spoon the chocolate mixture over the cake mixture in the tin, then run a fork through both mixtures, gently swirling the two together to create a marbled effect.
- Be careful not to swirl the mixtures together too much as you want to leave an obvious marble effect.
- Bake for 55–70 minutes, until the cake shrinks slightly from the sides of the tin. Test it is cooked by inserting a skewer into the centre and it comes out clean (test the cake after 55 minutes).
- Remove the cake from the tin and leave to cool on a wire rack.
- Once cooled, dust with icing sugar.