Place the sweet condensed milk in a baking dish and cover it with foil.
Place the dish in a large roasting pan and fill it up with water to create a water bath (bauño de maria). Bake at 400 degrees F for about 1 hour and 30 minutes. Check about every 25 minutes the water level and add more if necessary.
Remove from the oven and whisk until smooth. Let it cool and enjoy!