Cream butter and sugar, add beaten egg yolks. Sift flour with cream of tartar and mix soda in with milk. Add these alternately to creamed butter mixture. Beat egg whites until stiff. Fold gently into batter. Pour into 2 large well greased layer pans (9 inch). Bake at 350 for 30-35 minutes. ** Or you could make 1 loaf pan baking time approx 1 hr. ** Or you could make 9 by 13 pan baking time approx 37-42 min. ** Or you could make 2 - 8 inch pans and bake for 35-40 minutes. ** Or you could make 32 cupcakes and bake for 17-20 minutes.