I just love this simple, old-fashioned cake as it always reminds me of when I was little. Made using a basic Madeira cake recipe, the mixture is separated into two bowls, cocoa powder is folded into one and then the two mixtures are swirled gently together. This cake will keep for a couple of days in an airtight box, or it can be frozen. Serve it plain or dusted with icing sugar, or drizzle some hot chocolate sauce over the top.
Preheat the oven to 180°C (350°F), Gas mark 4. Butter and flour the sides of a 20cm (8in) diameter spring-form/loose-bottomed cake tin and line the base with greaseproof paper.
Cream the butter in a large bowl or in an electric food mixer until soft. Add the sugar and beat until the mixture is light and fluffy.
Whisk the eggs and vanilla extract together in a small bowl. Gradually add the eggs to the butter mixture, beating all the time. Sift in the flour and baking powder and fold in gently to mix, then add the milk and mix gently to combine.
Tip half of the cake mixture into another large bowl and, into this bowl, fold in the sifted cocoa powder.
Place the cake mixtures into the prepared tin by alternating spoonfuls of the vanilla batter with the chocolate batter, then with a skewer or similar implement, gently draw swirls through the cake mixture to ‘marblise’ it. Don’t overmix or you won’t have that wonderful marble effect. Bake in the oven for 45 minutes or until a skewer inserted into the middle comes out clean.
Turn the cake out onto a wire rack and allow to cool.