Heat oven to 425°F.Remove stem from mushroom and wipe clean with a damp paper towel. Spray both sides with cooking spray and place on an aluminum foil-lined baking sheet. Sprinkle with a small amount of minced garlic if desired. Bake 30 minutes, or until fork tender, turning once halfway through cooking time.Increase heat to broil.Top concave side of mushroom with tomato sauce and cheese. Place under broiler for 1 minute or until cheese melts and bubbles. Optional, add a sprinkle of grated Parmesan and season with salt and freshly ground black pepper to mimic breadcrumbs.