Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Cream 100 g butter, sugar and vanilla sugar in a large bowl with the whisks of the mixer. Stir in quark, lemon peel, cream and eggs.
Stir milk and starch until smooth, then stir in. Fold in the almonds. Pour the mixture into a well greased casserole dish (approx. 24 x 31 cm; 5 cm high) and smooth it down.
Place the mould in a fat pan (deep baking tray) and pour on so much hot water that the fat pan is almost full to the brim. Bake in a hot oven for 60-70 minutes and then remove carefully from the oven.
Let it cool down on a cake rack.
In the meantime, select the blueberries, wash carefully and drain well. Stir jam until smooth. Mix blueberries and jam and spread on the cake.