Knead the flour, salt, lemon zest and egg yolk and chill for 1 hour. Roll out the dough in a greased springform pan (edge approx. 3 cm high). Line the bottom with baking wafers. Halve the pitted and peeled apricots and spread on the wafers.
Separate the eggs, stir together the yolks, sugar and vanilla sugar until frothy. Add the cream, quark and almonds. Beat egg whites until stiff and fold in. Spread the mixture on the dough with apricots and bake in the preheated oven at 175 degrees for about 45 minutes.