Cut apples into eighths, peel them, remove the core and cut into not too large slices. Sprinkle with lemon juice immediately.
Sift the flour and baking powder into a bowl. Beat 5 egg whites with a pinch of salt until stiff. Slowly add about 1/3 of the sugar.
Cream butter with the remaining sugar. Gradually stir the 5 yolks, lemon juice and zest with the mixer until the sugar is dissolved.
First add the flour and baking powder mixture, then the beaten egg white to the yolk mixture. Spread the dough on a baking tray covered with baking paper or fill it into a springform pan (Ø 30 cm). Cover dough with apple slices.
Mix 2 tbsp. powdered sugar and 1/2 tbsp. cinnamon well and sieve over the apples. Sprinkle with sliced almonds.
Push the tray (or form) into the cold oven and bake at 180 °C U/O or 165 °C hot air for approx. 35 to 40 minutes.