Dissolve yeast in warm water, and set aside.
Scald milk; add shortening and sugar, stirring until shortening melts. Cool slightly. Add flour and salt; beat until smooth. Add yeast mixture; beat well.
Shape dough into a ball; place in a greased bowl, turning to grease top. Cover, and let rise in a warm place (85°), free from drafts, 1 1/2 hours or until doubled in bulk.
Punch dough down. Fill well-greased muffin pans about one-third full. Cover, and let rise in a warm place 45 minutes or until doubled in bulk. Bake at 425° for 15 minutes or until golden brown.