Peel apples, quarter them and cut out the core. Cut apple quarters into slices. Mix with lemon juice. Put 400 g cream in a mixing bowl, add 225 g sugar, salt, vanillin sugar and lemon peel and beat with the whisks of the hand mixer until half stiff.
Stir in the eggs one by one. Mix flour and baking powder, add and stir in briefly. Pour the dough into a greased fat pan (32 x 39 cm) sprinkled with flour. Spread apples on top. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 15 minutes.
In the meantime, melt butter for the topping, add 50 g cream and 100 g sugar. Bring to the boil while stirring. Remove from the heat and fold in the flaked almonds. Take the cake out of the oven, carefully spread the almond mixture on top and bake at the same temperature for another 18-20 minutes.
Remove from the oven and let it cool down. Whipped cream tastes good with it.