Preheat oven to 375°F.
Cut 1/4-inch slice from top of each onion; trim small amount from bottom end so onion stands upright.
Place half of onions in 8x8-inch microwave-safe dish; add 1/2 cup water and cover.
Microwave on HIGH for 12 minutes, or until onions are tender.
Carefully remove onions from dish and cool slightly.
Repeat with remaining onions and water.
When cool enough to handle, carefully remove inner layers of onions with paring knife, leaving about a 1/4-inch onion shell. I removed about 3 to 4 layers from each onion, depending on the size of the onion.
Chop and reserve 1 cup of the onion. Set aside remaining onion for another use.
Spray 13x9-inch baking dish with cooking spray.
Place 1 cup tomato sauce in bottom of dish.
Arrange prepared onion shells over tomato sauce; sprinkle with salt and pepper and set aside.
Heat large nonstick skillet over medium-high heat.
Add sausage; cook 4 to 5 minutes or until crumbled and no longer pink, stirring occasionally. Drain.
Add reserved 1 cup chopped onion and garlic; cook 2 to 3 minutes or until fragrant.
Stir in undrained tomatoes, remaining tomato sauce, 1/2 cup cheese and bread crumbs; stir to combine.
Spoon mixture into prepared onion shells.
Cover baking dish with aluminum foil.
Bake for 15 to 20 minutes or until heated through.
Remove from oven and sprinkle remaining 1/2 cup cheese on top of the onions.
Serve onions with a little sauce from the dish.