Pour 1 large tin of apricots into a sieve and drain well. Cream butter, 200 g sugar, vanillin sugar and salt with the whisk of the hand mixer. Stir the eggs one after the other into the fat-sugar mixture.
Stir in buttermilk as well. Mix flour, poppy seeds and baking powder and stir into the mixture quickly. Grease a fat pan of the oven (36 x 41 cm) and dust with flour. Add the dough and smooth it down.
Cut the drained apricots into large pieces and spread on the cake. Bake the cake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 25 minutes. Remove and let cool on a cake rack.
Mix cream cheese and 75 g sugar. Whip the cream and the cream firm with the whisk of the hand mixer until stiff. Stir the cream into the cream cheese and whip again until a creamy, firm mixture is formed.
Cut the cake into four equally sized plates. Place one cake base on a cake plate, spread about 1/3 of the cream on top, place another cake base on top and press down lightly. Repeat the process until the cream is used up, finish with a cake base.
Chill for about 1 hour.
Pour 1 small tin of apricots into a sieve and drain well. Cut the apricots into slices, spread on the cake, dust with icing sugar and serve.