Blueberry Kuchen

2 cups unbleached flour
2 teaspoons baking powder
1/2 teaspoon baking soda
1/4 cup butter
3/4 cup granulated sugar
1 large egg
1/2 cup milk
2 cups blueberries
Streusel Topping

Stir together flour, baking powder, baking soda and salt. Cream butter and sugar in large bowl. Beat in egg until blended. Add flour mixture and milk; stir just until moistened. Fold in blueberries. Turn into a buttered and floured 9-inch springform pan. Sprinkle with Streusel Topping. Bake at 375 degrees F for 45 to 50 minutes. If top begins to brown too quickly, cover with foil.

Streusel Topping
1/3 to 1/2 cup brown sugar
3 tablespoons flour
2 teaspoons cinnamon
3 tablespoons butter
1/2 cup chopped walnuts

Stir together brown sugar, flour, and cinnamon. Cut in butter with pastry blender. Stir in walnuts.