Drain and rinse beans if they are canned.
Blend together all ingredients except cheese, either in a blender or with a hand blender.
Transfer to a pot, and add the cheese, if using.
Heat on low, stirring occasionally until desired serving temperature is reached and optional cheese is melted.
If serving with pasta, stir in cooked pasta at this time. Add more milk of choice if a thinner sauce is desired.
Instant Pot Version: Instead of transferring to a pot on the stove, put the blended mixture in your instant pot and heat on manual for 5 minutes.