1 c. butter, softened
2 c. sugar
1 c. firmly packed brown sugar
6 lg.. eggs
2 1/2 c. all purpose flour
1/4 tsp. baking soda
1/2 c. cocoa
1 (8 oz.) sour cream
2 tsp. vanilla

Heat oven to 325 degrees. Grease and flour 10 inch tube pan. Beat butter with electric mixer for 2 minutes until soft and creamy. Gradually, add sugars, beating for 1 minute. Add eggs, one at a time, beating just until yellow disappears. Combine flour, baking soda and cocoa. Add to creamed mixture alternately with sour cream, beginning and ending with flour mixture. Mix at lowest speed just until blended after each addition. Stir in vanilla.

Spoon into prepared pan and bake for 1 hour and 20 minutes until wooden pick inserted in center comes out clean. Cool in pan for 15 minutes. Remove from pan, cool completely.