Apple Gratin with Wheat Berries
Grease a baking dish with butter and sprinkle with breadcrumbs. Preheat the oven to 180°C (approximately 350°F) convection. Rinse the apples, cut into quarters, remove the core and cut into wedges. Separate the eggs. Whisk the egg yolks, sugar, vanilla sugar and lemon zest together for about 5 minutes, until very frothy. Add the crème fraîche, quark and wheat berries and mix until combined. Whip the egg whites until stiff then fold in along with the semolina. Pour approximately 2/3 of the batter into the prepared pan, arrange the apple slices, overlapping slightly, over top then coat with the remaining batter.
Bake until golden brown, around 50-60 minutes. Serve dusted with powdered sugar.