2 potatoes, boiled and mashed
1 c. butter
1 1/2 c. sugar
4 eggs
3 c. flour
1 1/2 tsp. baking soda
1 1/2 tsp. baking powder

Cream together butter and sugar. Add 4 eggs, one at a time. Beat well after each addition. Stir in potato.

Sift together 3 times flour, baking soda, and baking powder. Add to cream mixture and mix well.

FILLING:

1 1/2 c. ground walnuts
3/4 c. brown sugar
3 tsp. flour
1 tsp. cinnamon

Mix all together, add 1 teaspoon vanilla and 2 cups sour cream to the walnuts, brown sugar, flour and cinnamon mixture. Grease and flour tube pan. Put a layer of batter, filling, batter and filling. Bake in 350 degree oven for 1 hour and 15 minutes. Let cool. Remove from pan and sprinkle with powdered sugar.