In a mixing bowl, combine 2 1/2 cups flour and yeast. In a saucepan, heat milk, margarine, sugar, and salt just until warm (115 to 120 degrees), stirring constantly until margarine almost melts. Add liquid to dry ingredients in mixing bowl along with egg whites. Beat at low speed for 1/2 minute, scraping sides of bowl constantly. Beat 3 minutes at high speed. Stir in remaining flour as you can mix in with a spoon. Turn out onto a lightly floured surface. Knead in enough flour to make a stiff dough that is smooth and elastic (6 to 8 minutes total). Divide dough into thirds. Shape each of 2 portions into loaves. Store in freezer container with a double thickness of waxed paper between. Divide remaining dough into 16 balls. Arrange balls 1" apart in a freezer container.
