Warm buttermilk only slightly, crumble yeast into it and dissolve. Put the sugar, vanilla sugar, flour, salt, butter and egg in a mixing bowl and pour the buttermilk-yeast mixture over it.
Knead with the dough hooks of the hand mixer to a smooth dough. Let the dough rise in a warm place for approx. 45 minutes. In the meantime drain the apricots on a sieve. Roughly chop the trail mix.
Knead the dough again with floured hands and place it evenly on a well greased baking tray. Leave to rise again for another 15 minutes in a warm place. Spread the apricots evenly on the dough and sprinkle with trail mix.
Bake in the preheated oven (electric: 175 °C/ gas: level 2) for 25-30 minutes. Dust with icing sugar.