Beat the fat, sugar and salt with the whisk of the hand mixer until creamy. Stir in the eggs one by one. Mix flour and baking powder. Alternately add the milk to the fat egg mixture and stir in. Halve the dough.
Stir lemon zest into one half. Stir cocoa, peanut butter and peanuts into the remaining dough. Grease a cake tin (2 1/2 litre capacity) and sprinkle flour. Pour in light and dark dough alternately by the spoonful. Pull through spirally with a fork and smooth it down. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 50-60 minutes. Remove from the oven, allow to cool slightly, turn out of the pan and allow to cool completely. For the icing, stir icing sugar and lemon juice until smooth. Colour delicately with food colouring.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 50-60 minutes. Remove from the oven, allow to cool slightly, turn out of the pan and allow to cool completely. For the icing, stir icing sugar and lemon juice until smooth. Colour delicately with food colouring. Cover the cake evenly with the icing and allow to dry. Whipped cream tastes good with it