Grease a tart pan and sprinkle with breadcrumbs. Thaw the puff pastry sheets and line the tart pan with them. Prick the bottom several times with a fork.
Wash the apples and cut out the cores with an apple cutter. Cut the apples into slices. Mix the apple slices in a bowl with a little cinnamon sugar and the lemon juice. Layer the apple slices in the mold. Whisk together the sour cream, eggs, sugar and lemon zest and pour over the apples.
Bake in a preheated oven (top / bottom heat: 200 ° C, gas: level 3) for about 45 minutes. Sprinkle with the rest of the cinnamon sugar while still warm.