Arizona Chicken

In a skillet, brown chicken on both sides in 2 tablespoons of oil.

Remove and set aside. In the same skillet, saute onion in remaining oil until tender.

Add the tomatoes, celery, water, olives, garlic powder, oregano, salt if desired and pepper; bring to a boil.

Cover and simmer for 15 minutes. Return chicken to pan. Simmer, uncovered, for 15 minutes.

Add mushrooms; simmer 15 minutes longer or until a meat thermometer reads 170°.