Cut butter into pieces. Knead butter, sugar, flour, vanilla sugar and egg first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Wrap the dough in foil and chill for about 30 minutes. Roll out the dough on a floured work surface approx. 2 mm thin and cut out castles (approx. 5 x 4 cm) and crowns (approx. 5 x 4 cm). Knead dough remains again, roll out and cut out. Put the biscuits on 2-3 baking trays lined with baking paper.
Bake one after the other in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 8-10 minutes. Let the biscuits cool down on a cake rack. Pass the jam through a sieve. Spread one half of the castle biscuits with the jam and cover with the remaining castle biscuits. Stir icing sugar, lemon juice and 2 teaspoons of water until smooth. Decorate the biscuits with icing, chocolate lentils and fruit gums
45 minutes waiting time