Wash the lemon and grate the peel. Squeeze the lemon. Cream fat, sugar and salt with the whisk of the hand mixer. Stir in the eggs bit by bit. Mix flour and baking powder and stir into the fat egg mass with sour cream, lemon peel and lemon juice.
Spread the dough on a greased baking tray (34x38 cm) and bake in the preheated oven (electric cooker: 175 °C/ gas: level 2) for 25-30 minutes and let it cool down. Whip cream until stiff, powdered sugar and 1 tablespoon cold water until smooth. Mark individual pieces on the cake with the icing. Decorate with cream and sweets. Makes approx. 16 pieces