Heat nonstick Dutch oven or 4-quart saucepan over medium-high heat. Add beef and onion; cook 5 minutes, stirring occasionally, until beef is browned.
Stir in potatoes, carrots, celery and mushrooms. Cook 2 minutes, stirring frequently. Stir in all remaining ingredients. Heat to boiling. Reduce heat to low; simmer uncovered 15 minutes or until vegetables are tender. If desired, sprinkle individual servings with chopped fresh parsley.