10" tube pan, well greased & floured (set aside), 1 stick butter (softened), 1 cup sugar, 2 eggs, 1 cup sour cream, 1 t. baking soda, 1 t. baking powder, 1 t. vanilla extract, 2 cups flour, 1 (12oz.) pkg chocolate chips (divided 3/4 into cake batter - reserve 1/4 for topping).
Cream butter with sugar, add eggs and beat. Add remaining ingredients one at a time beating batter well. Spoon batter into tube pan evenly (batter will be thick). Sprinkle reserved chocolate chips on top of batter evenly covering entire top. Lastly sprinkle topping on just before baking.
Topping: 1/3 cup brown sugar, 1 t. cinnamon, 1/4 cup chopped walnuts.
Blend topping ingredients in a small bowl and sprinkle evenly over top of chips on cake batter. Bake in a preheated 350 degree oven for 45 minutes. Cool completely in tube pan before removing. Store in an air-tight container to insure freshness.