In a heavy skillet, brown and crumble sausage over medium heat until fully cooked. Drain and set aside. In the same skillet, combine soup and milk. Add mustard, seasoned salt and pepper; bring to a boil.
Reduce heat. Add sausage and sour cream. Simmer until heated through (do not boil). Serve over warm biscuits. Yields 4-6 servings (3 1/2 cups gravy).