Separate eggs. Knead butter, flour, sugar, salt, vanillin sugar and egg yolks first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Wrap the dough in foil and let it rest for about 30 minutes. Roll out the dough 2-3 mm thinly on a floured work surface and cut out approx. 130 small circles (approx. 3 cm Ø), kneading and rolling out dough remains again and again. Place circles on 2-3 baking trays lined with baking paper. Beat the egg white until stiff, while letting the icing sugar trickle in. Fill firm beaten egg whites into a piping bag with star-shaped spout and sprinkle a little tuff on each cookie.
Bake the trays one after the other in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 20 minutes. Take out and let cool down. Warm up the redcurrant jelly and let it simmer for about 10 minutes. Let the jelly cool down, stirring again and again. Mix 2 biscuits with 1/2 tsp. jelly each. Let the biscuits dry for about 30 minutes
waiting time approx. 1 1/4 hours