Preheat the oven to 400 degrees F. Pour the sweetened condensed milk into a shallow baking dish - I like to use a loaf pan.
Cover the pan tightly with aluminum foil and set it inside a larger roasting pan. Pour in hot water to reach about halfway up the side of the smaller pan.
Bake 1 hour. Remove from oven and cool. It's ready to be used in your recipes! Store in a glass jar in the refrigerator up to 1 week.