Knudsen Coffee Cake

1 cup butter
1 1/4 cups sugar
2 eggs, beaten
1 cup sour cream
1 tsp. baking powder
1/2 tsp. baking soda
2 cups sifted flour
1 tsp. vanilla

Topping:
1/2 cup chopped nuts
2 Tbsp. sugar
1/2 tsp. cinnamon

Cream butter and sugar; add eggs, sour cream and vanilla. Beat well. Gradually add sifted flour, baking powder and baking soda. Mix well. Place half in buttered 9-inch tube pan and sprinkle with half of topping mixture. Place remaining dough on top and sprinkle with remaining topping. Bake in moderate 350 degrees oven for 1 hour. Sprinkle powdered sugar on top while still hot. Let cool 15 to 20 minutes before serving.