In a small bowl, mix: 4 egg yolks (save whites)

Put 1/2 of a large cake of yeast in 1/4 cup warm water. Add yeast mixture to sour cream and egg yolks. Stir all together and pour into flour mixture and work until hands come clean. Wrap in double piece of wax paper and put into refrigerator overnight or at least 4 hours.

Melt on stove, don't boil.

Pour milk and butter over nut mixture. Beat the 4 egg whites and blend them into nut mixture.

Divide dough into 6 pieces. Roll out thin and spread entire surface with nut mixture, roll like jelly roll. Grease pan well. Bake at 350 degrees for 20 minutes. Turn pan around, bake 20 more minutes at 325 degrees.