Cream butter and sugar at high speed until blended. Add eggs, 1 at a time. Add vanilla and butter flavoring. Alternate flour and baking soda with sour cream. Beat well.
Cook in greased and floured tube pan (10 inch) at 325°F. for 1 hour and 20 minutes to 1 hour and 30 minutes.
This cake freezes well, for at least 6 months. Can be baked ahead for use later. This cake can be baked in 2 loaf pans or 4 (1 pound) pans.