Streuselkuchen is a very popular type of cake all over Germany and Austria. There are many different variations, but the important part of a "streusel" is the crumbled topping. The verb "streuen" literally means "to strew/to disperse/to scatter", which refers to the topping which is usually a combination of flour, sugar, and butter.
This is one of my favorite recipes, but feel free to add whatever you'd like to the center of the cake. Fruits and nuts are wonderful additions.
1 cup butter
2 cups white sugar
1 cup sour cream
1 tsp vanilla extract
2 cups bread flour (all purpose is fine)
1 1/2 tsp baking powder
1/8 teaspoon salt
Filling and topping:
2/3 cup flour
1 cup brown sugar
4 tbsp melted butter
1 tbsp cinnamon
Preheat the oven to 350 degrees Fahrenheit.
Cream together the butter and white sugar until very light. Beat in the eggs one at a time, and then add the vanilla and sour cream. Mix the baking powder, salt and flour together and slowly incorporate it into the mixture.
At this point, pour half of the batter into a greased 9" spring-form pan. Mix together the ingredients for the topping in one bowl and spread half of it over the mixture. (I added some flat disks of marzipan on top of the crumbled layer and covered the entire cake.)
After this, pour the remaining batter on top, the cover the cake with the rest of the streusel mixture.
Bake the cake for approximately 1 hour. (Keep an eye on it for the last 15 minutes of baking. If it looks like the top is browning too much, take it out)