In a small bowl combine the 2 tablespoons butter, 2 tablespoons flour, and 1/3 cup of sugar using a fork or a pastry cutter cut in the butter until small crumbs form. Set aside.
Preheat the oven to 350 degrees F. Grease a 9-inch spring-form pan.
In a medium bowl combine the 3/4 cup sugar and 1/2 cup butter with a mixer beat until fluffy.
Add one egg at a time mixing just until blend.
Sift together the cup of flour, baking powder, and salt together. Add to the batter and mix just until it is mixed in.
Spread the batter into the prepared spring-form pan.
Top the batter with the cleaned blueberries. Sprinkle the topping over top of the blueberries.
Place the kuchen in the preheated oven for 40 to 45 minutes or until the topping is browned or a toothpick inserted comes out clean.
Remove from the oven and set on a cooling rack until room temperature.