Bohemian Kolaches

In a small bowl, dissolve yeast and 1 tablespoon sugar in warm milk; let stand 10 minutes. In a large bowl, combine 2 cups flour, remaining sugar, egg yolks, salt, butter and yeast/milk mixture. Mix until smooth. Add enough remaining flour to make a stiff dough. , Turn out onto a floured surface and knead until smooth and elastic, 6-8 minutes. Add additional flour if necessary. Place dough in greased bowl, turning once to grease top. Cover; let rise in a warm place until doubled in bulk, about 1 hour. , Punch dough down and allow to rise again. Roll out on floured surface to 1/2-in. thickness. Cut with large glass or 2-1/2-in. cutter. Place on greased baking sheets; let rise until doubled, about 45 minutes. , Firmly press indentation in center and fill each roll with a heaping tablespoon of filling. Brush dough with egg white. Bake at 350° for 10-15 minutes or until rolls are light golden brown.