Separate the eggs, beat the egg whites until stiff. Mix the egg yolks, quark, sugar, oatmeal, cinnamon and baking powder together.
Peel and chop apples and pears, either with the multi-chopper (Moulinette, Quickchef, etc.) or by hand. Then add the fruit to the quark mixture and stir in. Finally, carefully fold in the egg whites.
Put the mixture in an ovenproof dish, not too full, the dough will still rise, and sprinkle with the flaked almonds.
Bake for about 35 minutes at 170 ° C, until the casserole begins to brown nicely.