Mix the soft butter well until foamy. Gradually add sugar, vanilla sugar, eggs, grated orange peel and 1 tablespoon orange juice. Mix the flour, cornstarch and baking powder, sieve, stir in a tablespoon at a time. Finally, fold the almonds under the dough and fill it in a greased springform pan with a perforated base (wreath form), diameter 24 cm. Bake in a preheated oven at 175 ° C for about 50-60 minutes. Stir the sifted powdered sugar with enough orange juice to make a thick paste. Brush the cooled cake with it and garnish it with whole, peeled almonds.