Mix flour and baking powder in a bowl. Whisk the eggs in another bowl. Add sugar, vanilla sugar, oil and lemonade to the eggs and mix briefly. Add the flour mixture and fold in briefly until everything is just mixed
Grease a rectangular springform pan (24 x 35 cm) and dust with flour. Pour the dough into the form and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 30-35 minutes. Take out and let cool down on a cake rack
For the decoration, mix icing sugar, lemon juice and milk to a slightly thicker glaze. Divide the icing into 6 parts. Leave one part of the icing white, colour the rest of the icing differently with food colouring. Pour the white icing into a small freezer bag and cut off a small corner. Mark individual pieces on the cake with the icing. Pour the rest of the icing into small freezer bags and cut off small corners. Decorate with icing and sweets as you like
Waiting time approx. 1 hour