Cream butter and sugar, add eggs, and beat well. Blend in sour cream. Add dry ingredients and mix well. Spread half of batter into prepared 9-x-13-inch pan, spoon drained berries over batter. Sprinkle half of nut mixture over berries, cover with remaining batter, top with remaining nut mixture. Bake at 350 degrees for 25 minutes or until a toothpick inserted near the center comes out clean.