Combine the milk and vanilla in a saucepan. Heat over low heat until warm, and then sift in the powdered sugar. Slowly whisk until well blended, and then remove the glaze from the heat. Set over a bowl of warm water to keep warm, and then dip doughnuts into the glaze.
NotesThis recipe was provided by a chef, restaurant or culinary professional and makes a large quantity. The Food Network Kitchens have not tested it for home use and therefore cannot make any representation as to the results.