1 c  Butter, softened
1 c  Firmly packed brown sugar
2 1/2 c  All purpose flour
1/2 c  Cocoa
2 ts Vanilla
2 c  Sugar
6    Large eggs
1/4 ts Baking soda
8 oz Sour cream
Powdered sugar (optional)

Beat butter at medium speed about 2 minutes. Gradually add sugar, beating
at medium speed for 5-7 minutes. 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 low speed
just until blended after each addition. Stir in vanilla. Spoon batter into
a greased and floured 10-inch tube pan. Bake at 325F for 1 hour and 20
minutes or until a wooden pick inserted in center comes out clean. Cool in
pan on a wire rack. Sprinkle with powdered sugar, if desired.