Grease a fat pan (approx. 32 x 39 cm; at least 3.5 cm deep) and dust with flour. Cream butter, 350 g sugar, 1 vanillin sugar, lemon peel and 1 pinch of salt. Stir in the eggs one by one.
Mix flour and baking powder and stir in portions briefly. Spread the dough on the fat pan. Bake in the preheated oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2) for approx. 25 minutes.
Mix icing sugar and 100 ml lemon juice. Take the cake out of the oven and sprinkle it immediately. Let it cool down.
Drain the apricots, put about 20 halves aside (the rest of the apricots and juice can be used elsewhere). Mix mascarpone, quark, 2 tablespoons lemon juice, milk, 75 g sugar and 1 vanillin sugar only briefly.
Whip cream until stiff, fold in.
Cut the cake into about 20 pieces. Put 1 tablespoon of cream on each piece and place 1 apricot half on top.