Peel apples, quarter them and cut out the core. Cut quarters into thick slices. For the dough, whisk eggs, sugar, salt, vanillin sugar and lemon zest with the whisk of the hand mixer until thick and creamy.
Stir in yoghurt. Mix flour and baking powder, sieve onto the egg-sugar mixture and stir in. Put the dough into a greased springform pan (26 cm Ø) sprinkled with breadcrumbs, smooth it down and put the apples loosely on top in several layers.
If necessary, press lightly several times so that the apples sink into the dough. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 50 minutes. In the meantime, pass the jam through a fine sieve.
Remove the cake, place it on a grid and immediately spread with the jam. Remove from the edge of the springform pan and allow to cool in the pan. Remove from the mould and dust with icing sugar. Serve with vanilla yoghurt.