Drain the cherries, reserving the juice. Stir the cornstarch and the indicated amount of juice. Bring the rest of the juice to the boil with half of the sugar (1) and a little bit of cinnamon. Stir in cornstarch and cook for about 1 minute. Fold in cherries. Allow to cool.
Melt butter (1).
Cream butter (2) and sugar (2). Fold in juice of one lemon and ground almond kernels.
Separate the eggs. Mix sugar, egg yolks, curd (3), vanillin sugar, lemon zest and semolina until smooth. Fold in liquid butter. Whip egg whites until stiff, sifting in remaining sugar (1). Fold the whipped cream into the curd mixture.
Grease a gratin dish (approx. 20 x 30 cm for 4 servings) and sprinkle with breadcrumbs. Spread half of the curd mixture into the dish. Spread cherry compote evenly on top. Spread remaining curd mixture on top. Spread almond mixture evenly on top.
Bake in the heated oven on the second rack from the bottom (electric oven: 175 degrees / convection oven: 150 degrees / gas: level 2) for about forty minutes until golden brown.
Toast the almond flakes. Sprinkle over the casserole with the powdered sugar. Decorate with lemon balm if desired.