Preheat oven to 180 C.
Peel the apples, remove the seeds. Cut into thin slices as much as possible using mandolin or knife. Mix with cinnamon.
In a big bowl, beat the eggs and sugar, vanilla extract until fluffy. Add the butter, salt, milk. Stir to combine. Add the flour, baking powder. Mix well.
Add the peeled apples to the batter. Gently mix until all slices are coated.
Line the round baking pan (22 cm) with parchment paper. Pour the batter into the pan. Sprinkle the almond flakes over the cake.
Bake about 35 min. Allow the cake to cool. Remove from the pan. Dust with icing sugar.