what's the best way to make my Christmas icing ?
It depends on what you are using it for. If it's for cookies, sift some confectioners' sugar into a bowl. Or shake it through a sieve. You want to get rid of the lumps. Then very slowly and carefully add, a tiny spoonful at a time, a liquid like orange juice, or milk, or lemon juice, or even a nice liqueur and stir it well before adding any more. Add drops of liquid until you get it to a good spreading consistency. For cakes and other more elaborate desserts, you might want something a bit more complex, made with butter or cream cheese and confectioners' sugar, and flavorings. ;o)
What does Christmas Icing mean to you? And what will it be applied to? This term is confusing to me. Do you mean Royal Iceing for decorating sugar cookies?