2 c. flour
2 tsp. baking powder
1 tsp. baking soda
1/4 tsp. salt
10 tbsp. butter, divided
1/2 c. chopped walnuts
1/4 c. brown sugar
3 tsp. pure vanilla
1 c. sugar
2 eggs, beaten
1 c. mashed banana
1/2 c. sour cream

Combine flour, baking powder, baking soda and salt; set aside. Combine 2 tablespoons of butter with walnuts, brown sugar and 1 teaspoon of vanilla. Mix with a fork until mixture is crumbly; set aside.

Cream together remaining butter and the sugar until light and fluffy. Combine eggs with bananas, sour cream and remaining vanilla; blend into butter and sugar mixture. Gradually blend in flour mixture; stir just until batter is blended.

Remove 1/4 cup of the brown sugar-nut mixture for use later. Pat remaining sugar-nut mixture in an even layer in a greased 9 x 5 x 3 inch loaf pan. Top with batter; spread smooth. Sprinkle with reserved sugar-nut mixture. Bake in 350 degree oven for 50 minutes.