Cook egg noodles as per directions. In a large skillet over medium heat, heat magarine. Cook mushrooms 3 minutes until limp. Increase heat to high. Cook, stirring constantly, 1 to 2 minutes or until excess moisture has evaporated from skillet. Add remaining ingredients, except sour cream and green pepper. Bring to a boil, stirring constantly. Reduce heat to medium. Simmer, uncovered, 5 minutes, stirring occasionally, until heated through. Remove skillet from heat, stir in sour cream. Serve over egg noodles, garnish with green pepper. Serves 4.