Mix flour, 150 g sugar, vanillin sugar and salt in a bowl. Add 2 eggs and spread butter in cubes on top. Work well with the dough hooks of the hand mixer. With cool hands quickly knead to a smooth dough.
Wrap in foil and refrigerate for about 1 hour. In the meantime, dice plums and apricots very finely for the filling. Mix with apricot liqueur and let stand for about 30 minutes. Then stir the remaining sugar, almonds and lemon peel into the marinated fruits.
Roll out the dough on a floured work surface to a thickness of 2-3 mm. Cut out stars of about 6.5 cm Ø. Put half of the stars on two baking trays lined with baking paper. Place some filling (approx. 1/2 teaspoon) in the middle of each star.
Cut the remaining stars crosswise in the middle. Separate remaining egg. Spread the edges of the filled stars with egg white and cover each with an incised star. Press the edges well.
Mix the egg yolk and cream and brush the stars with it. Sprinkle with flaked almonds and bake the trays one after the other in a preheated oven (electric oven: 200 °C/ gas: level 3) for 12-15 minutes.
Let stars on a cake rack cool down well. Keep in tightly closed tins.