Wash 6 apricots, rub dry, halve and stone them. Cut 6 apricots and boil water over them. Peel skin. Halve and stone the fruits and cut into cubes.
Mix fat, sugar, vanilla sugar and 1 pinch of salt with the whisk of the hand mixer until thick and creamy. Stir in the eggs one after the other. Mix flour, baking powder and hazelnuts and stir in alternately with the apricot liqueur.
Carefully fold in the diced apricots. Pour the dough into a greased springform pan (26 cm Ø) sprinkled with flour. Cover generously with remaining apricots. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 50 minutes.
Remove the cake from the oven, place it on a cake rack and remove it from the edge of the springform pan. Let it cool down. Wash the mint, dab dry and dust with icing sugar. Decorate the cake with mint and icing sugar.