Step 1

Spray 6-quart oval slow cooker with cooking spray. Trim tops off bell peppers; remove ribs and seeds. Set aside.

Step 2

In 12-inch nonstick skillet over medium-high heat, cook beef, onions, salt and pepper 8 to 10 minutes, stirring frequently, until beef is cooked through and onion softens. Add garlic; cook 15 seconds. Drain.

Step 3

Stir rice and 1/2 cup of the tomato sauce into beef mixture in skillet; mix to combine. Stir in 1 cup of the cheese. Stuff peppers with beef mixture; arrange in slow cooker. Pour remaining tomato sauce over peppers.

Step 4

Cover; cook on Low heat setting 4 1/2 to 5 1/2 hours or until peppers are soft. Top peppers with remaining 1 cup cheese. Cover; cook 3 to 8 minutes longer or until cheese is melted.

Step 5

Use slotted spoon to lift peppers from slow cooker.