Dissolve yeast in warm water in large mixer bowl. Add sugar, salt, egg, shortening and 1 cup flour. Beat until smooth. Stir in remaining flour; continue beating until smooth. Scrape batter from side of bowl. Cover; let rise in warm place until double, about 1/2 hour. Stir down batter and spoon into greased muffin tins. Let rise until double, about 30 minutes. Heat oven to 400°. Bake rolls about 15 minutes.