Grease a fat pan (approx. 32 x 39 cm; at least 3.5 cm deep) and dust with flour. Sort blueberries, wash if necessary and dab dry. Cream butter, 200 g sugar, 1 pinch of salt and lemon peel.
Stir in 4 eggs one by one. Mix flour and baking powder and stir in alternately with lemon juice and milk.
Spread the dough on the fat pan. Spread blueberries on top. Mix crème fraîche, 6 eggs, 100 g sugar and vanilla sugar. Spread the icing on the blueberries. Sprinkle with flaked almonds.
Bake in the preheated oven (electric oven: 175 °C/circulating air: 150 °C/gas: see manufacturer) for 45-50 minutes. Let them cool down. Sprinkle with 2 tablespoons of sugar before serving.