For rolls, stir together 1 1/3 cups warm milk, 2 packages yeast, and 1 tablespoon sugar in large bowl. Let stand 5-10 minutes or until foamy. Add 1/2 cup butter, 3 tablespoons sugar, 2 egg yolks, 1 teaspoon vanilla and 3/4 teaspoon salt. Mix with electric mixer using dough hook on medium speed until combined. Gradually add 4 cups bread flour, 1 cup at a time, and mix on medium speed until a smooth, elastic dough forms, about 5 minutes.