In a small bowl, dissolve yeast in warm water. In a large bowl, combine 3-1/2 cups flour, sugar and salt. Cut in butter until crumbly. Combine egg and warm milk; add to the crumb mixture. Stir in yeast mixture. Beat until smooth. Add enough remaining flour to form a firm dough.
Turn onto a lightly floured surface; knead until smooth and elastic, about 5-7 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 1 hour.
Punch dough down. Turn onto a lightly floured surface; divide in half. Roll each portion into a 12-in. circle. Spread with butter; sprinkle with garlic powder and cheese. Cut each into 12 wedges. Roll up wedges from a wide end and place point side down on greased baking sheets.
In a small bowl, beat egg and water. Brush over dough. Sprinkle with sesame seeds. Cover and let rise in a warm place until doubled, about 40 minutes.
Bake at 350° for 16-18 minutes or until golden brown. Remove to wire racks.