Kolaches (Czechoslovakia)

6 tablespoons lukewarm milk
2 packages active dry yeast
1 teaspoon salt
2 tablespoons granulated sugar
1/2 cup soft butter
4 eggs
4 egg yolks
4 cups all-purpose flour

Add yeast to milk and let stand several minutes to dissolve. Stir in salt and sugar. Put butter into a large bowl; add 1 whole egg and 1 egg yolk, beating very hard. Continue adding 1 whole egg and additional yolk, followed each time by hard beating. When all the eggs have been used, mix in yeast and then flour, beating hard. Cover with a towel and place in a warm place until double in size.

Pinch off pieces of dough the size of a large walnut. Place 2 inches apart on a greased baking sheet; cover, and let rise in a warm place for 30 minutes.

Press a hollow in the center of each piece with fingers and fill the cavity with Prune Filling, jam or marmalade. Bake at 350 degrees F for 20 to 25 minutes. Remove from oven. When cool, sprinkle tops generously with sugar.

Prune Filling:
1 pound prunes, cooked
1 tablespoon granulated sugar
1 tablespoon butter, softened
1/2 teaspoon cinnamon
1/2 teaspoon vanilla extract

When prunes are tender, drain; discard pits and chop prunes coarsely. Stir in sugar, butter, cinnamon and vanilla extract. Add more sugar if desired.