Pasteurized Egg Whites
The first very important thing to note, when creating royal icing, you MUST use pasteurized egg whites in this recipe if you intend to eat your gingerbread house at all. You can buy pasteurized eggs, or you can make them by placing your egg whites into a double boiler, that has water at 140°F and warm the egg whites until they reach 140°F on a thermometer. Be careful to not let your water temperature go over 142°F or your eggs will cook.