Preheat oven to 325Ëš. Grease and lightly flour one 10 inch tube pan.
Sift SWANS DOWN Cake Flour, lightly spoon into measuring cup for 3 cups.
In large mixing bowl, combine butter, sugar and sour cream; mix until creamy. Add eggs, 1 at a time, beating until blended, add in butter flavor. Gently blend in SWANS DOWN Cake Flour until blended. (Do not over blend as this will yield a dry cake)
Bake approx. 1 hour and 15 minutes or until a long tester inserted into middle of cake comes out clean.
Cool in pan on a wire rack 10 to 15 minutes; remove from pan, and let cool completely on wire rack.