1. With a damp cloth wipe off the mushrooms, and cut the stem down so the mushrooms will lay flat. Place mushrooms in a bowl and add 2 tablespoons olive oil, Italian dressing, balsamic vinegar, onions and garlic. Let marinade 15-20 minutes, turning once.
2. Preheat grill to medium high heat. Lightly oil grill grate.
3. Remove Portobello mushrooms from bowl and place on grill, keeping marinade to brush on mushrooms while grilling. Cook 3-4 minutes per side until tender.
4. Quickly remove Portobello mushrooms from grill and place topside down. Add chopped bacon and top with cheese.
5. Place on your favorite roll and add condiments.
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