In a small bowl, combine seasoning mix and water; set aside. In a large skillet, saute beef in oil until no longer pink; drain. Add the mushrooms and seasoning mixture. Bring to a boil. Reduce heat; cover and simmer for 5 minutes. Stir in the sour cream and peas; heat through (do not boil). Serve over noodles. Yield: 6 servings.