Prepare the Serving Bowls: Place 1 tablespoon of butter in each of four bowls.
Simmer: In a saucepan over medium heat, bring the milk, cream, and oyster liquor to a simmer and reduce the heat to low. Add the oysters and simmer for 2 to 3 minutes or until the edges of the oysters cool and they are heated through. Season the stew with salt, pepper, and cayenne pepper to taste.
Garnish and Serve: Ladle into hot bowls and top with chopped parsley or chives. Serve with saltines or oyster crackers.