Dissolve yeast in warm water; stir in 1 tbsp sugar. Let stand 5 minutes.
Add milk, shortening, eggs, salt, 3 cups flour, and 1/3 cup sugar. Beat on medium speed for 2 minutes.
Stir in enough of the remaining flour to form a soft dough (will be sticky). Do not knead. Refrigerate, covered, overnight.
Punch dough down and turn out onto a lightly floured surface. Cut into 24 equal portions. Cut each portion into thirds. Roll each third into a ball. Place three balls into each greased muffin cup. Cover and rise in a warm place until doubled, about 1 3/4 hours.
Heat oven to 350* F. Bake rolls for 13-15 minutes or until golden brown. Remove from muffin tins to wire racks. Serve warm.