Combine milk and shortening; stir until shortening melts. Let cool to 105° to 115°.
Add yeast, stirring until dissolved. Add eggs, sugar, and salt; beat well. Gradually add flour, stirring until smooth. Cover and let rise in a warm place (85°), free from drafts, 1 hour or until doubled in bulk.
Punch dough down; spoon into greased muffin pans, filling two-thirds full. Cover and repeat rising procedure 1 hour or until doubled in bulk. Bake at 350° for 18 minutes or until golden brown. Brush top of muffins with butter. Remove from pan; place on wire racks to cool.