German Apple Streusel Pie

Combine the sliced apples with cinnamon in a heat-resistant container and gently warm it over low heat for 10 minutes, adding just enough water if needed to prevent the apples from burning. Remove it from heat and let it cool down naturally.

Preheat your oven to 350 degrees Fahrenheit (175 degrees Celsius). Grease a 10-inch round cake pan with melted butter to prevent the cake from sticking.

In a large mixing bowl, cream together the softened butter, granulated sugar, and vanilla sugar until you achieve a smooth consistency. Using an electric mixer, beat in the egg until well combined. In another bowl, whisk together the flour and baking powder. Gradually add 2/3 of the flour mixture to the butter mixture, beating on low speed. Add the remaining flour mixture and mix by hand until you achieve a crumbly texture.

Transfer half of the dough into the prepared cake pan and press it down firmly to create a base layer. Arrange the apple slices, leaving about 1 inch of space around the edges to allow for expansion during baking. Sprinkle the remaining dough evenly over the top of the apples.

Bake the cake in a preheated oven until the streusel topping and crust are lightly browned, approximately 50 minutes. Remove it from the oven and let it cool on a wire rack for 5 minutes. Use a table knife to loosen the edges and carefully transfer the cake to a serving plate or cooling rack.