Preheat oven to 400°.
Pour milk into a 9-inch pie plate, and cover with foil. Place pie plate in a shallow roasting pan. Add enough hot water to pan to come halfway up sides of pie plate (about 4 cups). Bake at 400° for 1 1/2 hours, adding additional water as needed (about 2 cups).
Carefully remove pie plate from water. Uncover, and stir milk with a whisk until smooth. Milk should be golden brown.