Wash the lemon with hot water, dry it and grate the peel finely. Then cut the lemon in half and squeeze out the juice. Peel the apples, quarter them, remove the core and grate as much of them finely on a grater until you have approx. 300 g (the graters go into the batter). Cut the rest of the apple quarters into thin wedges (put the wedges on top of the cake). Drizzle everything with lemon juice so that the apples don't turn brown.

Using the hand mixer, stir the butter, sugar and vanilla sugar in a large bowl on the highest setting until frothy. Stir in the eggs one at a time for about 1/2 minute at the highest level. Briefly stir in lemon zest and quark. Briefly stir in the grated apple (you may need to squeeze it out beforehand if there is juice).

Mix the flour, cornstarch, baking powder, salt and almonds and stir briefly into the dough on a low heat. If the dough is too firm, add a sip of milk if necessary. The dough shouldn't be too runny or too firm.

Fill the dough into a greased springform pan (diameter 26 cm) sprinkled with breadcrumbs and cover with the thin apple slices in a circle. Bake in the preheated oven on the middle rack for approx. 50 - 70 at 180 degrees top / bottom heat (or 160 degrees convection). Cover with aluminum foil after a baking time of 40 minutes if the surface becomes too dark.

Let the finished cake cool on a wire rack. Carefully remove from the mold and dust with powdered sugar if you like.

As an alternative, you can simply leave out the apple wedges on the cake surface. Then cover the cooled cake with icing sugar and sprinkle with roasted almond flakes.