Pour the apricots into a sieve, collect the juice. Cut the fruit into slices. Cut the biscuits in half.
Whisk butter, salt, 250 g sugar and vanillin sugar with the whisk of the hand mixer until thick and creamy white. Stir in the eggs one after the other. Mix flour and baking powder and stir in alternately with the milk. Fold in apricots and biscuits.
Grease the pancake tin (approx. 2 litres capacity) and sprinkle with sugar. Spread the dough evenly. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 45-60 minutes.
Take the cake out of the oven, let it rest for about 10 minutes and carefully turn it over onto a grid. Mix 5 tablespoons apricot juice and liqueur. Spread the cake with it. If necessary, sprinkle with 1 teaspoon of sugar. Let the cake cool down and cut into slices.