Cream butter and sugar. Add Solo. Add egg yolks, one at a time, beating after each. Blend in vanilla and sour cream. Sift together flour, soda and salt. Add gradually. Fold in stiffly beaten egg whites. Pour into greased tube or bundt pan. Bake at 350 for 1 hr 15-20 mins. Drizzle with glaze made with powdered sugar and milk 12:05 PM