1 1/4 lb boneless beef round steak (1/2 to 3/4-inch thick)
1 (8oz) pkg sliced fresh mushrooms (3 cups)
1 large onion, sliced, separated into rings
1 (10 3/4 oz) can condensed French onion soup
1 (6oz) pkg 10 minute herb stuffing mix
1/4 cup margarine or butter, melted
4 ounces (1 cup) shredded mozzarella cheese
Cut beef into 6 serving sized pieces. Layer half each of beef, mushrooms and onion in 3 1/2 to 4-quart slow cooker; repeat layers. Pour soup over ingredients in slow cooker. Cover; cook on low setting for 8 to 10 hours or until beef is tender and no longer pink.
Before serving, in medium bowl, combine stuffing mix, contents of seasoning packet, melted margarine and 1/2 cup of liquid from slow cooker; toss to mix. Place stuffing on top of contents in slow cooker. Increase heat to high setting. Cover; cook an additional 10 minutes or until stuffing is fluffy. Sprinkle with cheese. Cover; cook until cheese is melted.