Dissolve yeast in lukewarm water. Scald milk and set aside until lukewarm, not cold. Cream butter and sugar until light and fluffy. Add salt and mix again. Place dissolved yeast in milk. Add 3 cups flour and beat well. Stir in the creamed mixture and beat again. Then add unbeaten eggs and blend. Gradually add remaining flour, a tablespoon at a time, until dough is smooth enough to handle, then knead in remaining flour on a warmed board. The dough should be smooth and elastic to the touch, never hard nor stiff. Place in a greased bowl, cover, and allow to stand in a warm place about 2 1/2 hours until double in bulk. Place dough on a warmed board, which has been slightly floured. Pat down dough to about 1/4 inch thickness. Cut into 2 inch squares. Place a teaspoon of filling (recipe below) on each square and gather up the 4 corners carefully, folding one on top of the other, and press together so that folded dough is thinner than dough beneath the filling. When folded correctly, the filling will peek through the four sides. Place on a large cookie sheet about 2 inches apart. Let rise until double in bulk in a warm place, about 45 minutes. Bake at 375-F for 25 minutes. When cool sprinkle generously with powered sugar. Makes about six dozen cakes. PRUNE FILLING: Wash prunes and cook in enough water to cover. Bring to boil. When cool, strain, pit and chop well. Sweeten and add cinnamon to taste or orange peel. Allow to cool slightly before spreading. POPPY SEED FILLING: Combine ingredients and cook about five minutes until thick. APPLE FILLING: Cook together about five or six minutes until apples are soft. Cool.