Oma's Apple Cake

This was one of my favorite things growing up, especially the top part at the outer edge which is just so light and crunchy and well delicious.  My oma would make it every Thanksgiving and Christmas but since my family has never made it to dessert on a holiday, I was always allowed to have it for breakfast the next morning.

For the crust
200gr flour
80gr sugar
1/4 tsp baking powder
1 stick of butter, softened at room temperature
1 egg
1 tbsp vanilla sugar
small pinch of salt

Filling
about 2lbs macintosh apples, small to medium
2 tbsp almond flour

Topping
3 eggs, separated
150 gr sugar
juice of half a lemon
2 tbsp flour

powdered sugar

1. Preheat the oven to 375.  To form the crust whisk the baking powder, flour, sugar, vanilla sugar, and salt together.  Using your fingertips, a fork, or a pastry cutter to work the butter into flour mixture until it looks like breadcrumbs like you're making biscuits. Then work the egg in to form a dough, if its a bit dry and crumbly, add in a bit of milk.  Wrap in plastic wrap and rest in the fridge for at least 15 minutes.  Spread the dough onto the bottom of a spring form pan and bring slightly up the sides, about 3/4 of an inch.
2. Peel, quarter, and core the apples. Make shallow slits across the apples.  Arrange them in concentric circles in the pan and sprinkle with the almond flour.
3. Bake for about 30 minutes or until the crust and apples are slightly golden.
4. While the crust and apples are baking, beat the egg whites and lemon juice until stiff peaks.  Beat the egg yolks, sugar, and flour together.  Fold the egg whites into the egg yolk mixture.
5. Top the cake with the egg mixture and return to the oven until the top is golden brown and it only jiggles slightly when the pan is shook.
6. wait until it is completely cooled, run a thin bladed knife along the inside of the pan before you open the pan.  Top with powdered sugar