Dissolve yeast in warm water in large bowl.
Mix in milk, sugar, salt, shortening and 2 1/2 cups of the flour; beat until smooth.
Stir in enough remaining flour to make dough easy to handle.
Turn dough onto lightly floured board; knead until smooth and elastic, about 5 minutes.
Place in greased bowl; turn greased side up.
Cover; let rise in warm place until double, about 1 1/2 hours.
Punch down dough; turn onto lightly floured board and divide into 24 pieces.
Shape each piece into smooth ball.
Place each ball in a greased muffin cup or place balls about 3 inches apart on greased baking sheet.
Cover; let rise until almost double, about 45 minutes.
Heat oven to 275°.
Bake 20 to 30 minutes (do not allow rolls to brown).
Remove from pans and cool at room temperature.
Wrap, label and freeze.
15 minutes before serving, heat oven to 400°.
Remove rolls from freezer and unwrap; place on un greased baking sheet.
Bake until brown and hot, 7 to 10 minutes.