Slow Cooker Swiss Steak

1 large onion, quartered and sliced
1/4 cup all-purpose flour
1 teaspoon dried parsley flakes
1/2 teaspoon salt
1/8 teaspoon ground black pepper
1 pound round steak, cut into 4 portions
1 cup chopped celery
1 can (14.5 ounces) diced tomatoes
1 can cream of mushroom soup

Spray crockpot with cooking spray. Place sliced onion in bottom of crock. In a shallow plate, combine the flour, parsley, salt, and pepper. Dredge each steak portion in the flour mixture, then pound with a meat mallet to tenderize and flatten somewhat. Place beef in crockpot over onions.

Top with chopped celery. In another bowl, combine the tomatoes with cream of mushroom soup and any remaining flour mixture. Spoon soup mixture over all. Cover and cook on LOW for 7 to 9 hours, or until steak is tender. Serve with potatoes and a green vegetable or salad. Serves 4.