Marble cake

For 12 pieces

500 g wheat flour type 00
200 g sugar
6 eggs
250 g butter (room temperature)
80 ml milk
15 g baking powder
1 pinch of salt
zest of 1 lemon
3 tbsp cocoa powder (unsweetened)

Beat the eggs with the sugar and milk in a bowl until creamy. Mix in the butter, the lemon zest, a pinch of salt and the baking powder.
Add the flour and mix everything into a fine dough. Place 1/3 of the dough into a bowl, cover and rest at room temperature.
Add the cocoa powder to the larger amount of dough and mix well.
Pour the dark batter into a buttered loaf tin and bake at 180° hot air for about 45 minutes. After baking and testing with a wooden chopstick (if the dough sticks to the wooden chopstick, it is not yet cooked), allow the cake to cool slightly and remove from the loaf tin.
Cut the chocolate cake into slices and cut out hearts with a biscuit cutter or freehand. Then butter the loaf tin again and pour in a thin layer of the remaining white batter. Place the chocolate hearts close together in the batter and pour on the remaining white batter. The hearts should be completely covered.
Bake again at 180° hot air for 45 minutes. Remove from the oven (test again with a stick) and leave to cool.
Sprinkle with icing sugar and serve.

TIP: For red hearts, colour the pastry with the juice of cooked raspberries or currants instead of cocoa powder
(alternatively red food colouring, 2 teaspoons if powdered or 5 drops).