1 Beat the butter with the icing sugar, vanilla sugar and egg yolks until light and fluffy. Add the almonds and flour and quickly knead to a smooth dough. Wrap in clingfilm and chill for 1 hour.
2 Roll out about 3 mm thick on a lightly floured work surface and cut out 3-4 cm circles. Cut small stars or hearts out of half the circles. Lay on a baking tray lined with baking parchment.
3 Form the remaining pastry into a ball, roll out and cut out small rectangles using a pastry wheel. Lay on the baking tray.
4 Bake in a preheated oven (180°, middle shelf) for about 10-12 minutes, until lightly browned. Remove from the baking tray by pulling off with the paper and leave to cool.
5 Dust the biscuits with the cut-out stars and hearts with icing sugar. Gently heat the raspberry jelly, stir until smooth and spread on the whole biscuits. Sandwich the biscuits together in pairs (one whole biscuit with a cut-out biscuit). Spread half the rectangular biscuits with jelly, dust the others with a pattern of icing sugar and sandwich together in pairs.