Sift flour with baking soda.
Cream butter and sugar.
Beat egg yolks, add sour cream and flour mixture.
Add 1-2 teaspoons vanilla, 1 teaspoon almond or 11 teaspoons orange and 1 teaspoon lemon.
Fold in stiff egg whites, pour into greased floured tube pan.
Bake 1 hour at 300° or until done.