This recipe doesn't call for proofing the yeast but it's easy to do. Simply dissolve the yeast in the warm milk and let it stand for 5 minutes. If the yeast gets nice and foamy, add it to the flour mixture and proceed with the recipe as written. If it doesn't, start over with new yeast. These buns are best served warm. To reheat them, wrap them in foil and warm in a low oven for 20 minutes.