Put the flour in a bowl and press a depression in the middle. Add sugar and lukewarm milk to the hollow and crumble the yeast into it. Using a spoon, mix the yeast with the milk and some flour.
Add the egg, fat, 1 pinch of salt and lemon zest and knead everything into a smooth yeast dough. Cover and leave to rise in a warm place for about 30 minutes. Meanwhile peel the apples and, depending on their size, halve or quarter them and remove the seeds.
Cut apple pieces. Grease a baking dish (30 cm Ø) and sprinkle with breadcrumbs. Knead the dough well and roll it out to a circle (approx. 34 cm Ø) and put it into the form. Place apple pieces on the dough.
Let it go for another 20 minutes. Mix sour cream, Calvados, eggs, sugar and cinnamon. Pour the icing over the apples and bake in the preheated oven (electric: 200 °C/ gas: level 3) for about 40 minutes.
Let the cranberries drip off a little and spread them over the heifer. Dust with powdered sugar. Serve lukewarm. Makes about 12 pieces.