For the dough, put the butter, sugar, flour, baking powder, salt and eggs in a bowl and stir. Place the dough on a parchment-lined baking sheet and smooth it out.
Quarter, core and peel the apples. Cut the round side of the apple quarters lengthways several times (7 to 10 times). Press the apple slices into the dough with the incised side facing upwards, 7 x 4 pieces fit on a normal sheet. Mix the cinnamon and sugar, sprinkle on the tray. For the crumble, knead the ingredients and crumble over the tray.