In a large bowl, dissolve yeast and 2 teaspoons sugar in warm milk; let stand for 5 minutes. Add the butter, salt, egg yolks, remaining sugar and 2 cups flour; beat until smooth. Stir in enough remaining flour to form a soft dough. Cover and refrigerate egg white.
Turn dough onto a floured surface; knead until smooth and elastic, about 6-8 minutes. Place in a greased bowl, turning once to grease the top. Cover with plastic wrap and let rise in a warm place until doubled, about 1 hour.
Punch dough down. Turn onto a lightly floured surface; divide into fourths. Roll each portion into a log and cut each log into eight equal-sized pieces.
To form knots, roll each piece into a 10-in. rope; tie into a knot. Tuck ends under. Place all rolls on one large greased baking sheet. (The rolls will be close together.) Cover and let rise until doubled, about 30 minutes.
Brush egg white over rolls. Bake at 350° for 10-13 minutes or until golden brown. Remove from pan to a wire rack to cool. Serve warm or room temperature.