Whichever method and type of milk you use. Here's a tip about milk and hot foods. Add the milk SLOWLY. And stir while you're doing it. If you're using regular milk and it's been in the refrigerator OR if the evaporated milk is cold, the hot soup can (and probably will) curdle it. Using the method described above in steps #3 of the Stovetop and Instant Pot directions almost always keeps this from happening.