Stuffed Portabella ' Burgers '

• 6 portabella mushrooms (4-5 ounces each, stems removed, caps wiped with a damp paper towel)
• 1 large red onion (6 1/4-inch slices, slightly smaller than mushroom caps)
• 6 tablespoons extra virgin olive oil, plus extra
• extra virgin olive oil, for drizzling
• 1 loaf ciabatta, halved horizontally and cut in 6 pieces or 24 inches square pieces herbed focaccia bread
• 2 tablespoons balsamic vinegar
• 1 garlic clove, crushed through a press
• 12 teaspoon salt
• 12 teaspoon fresh ground black pepper
• 12 ounces Fontina cheese, cut in 6 slices
• 18 large fresh basil leaves, plus extra for garnish
• 6 slices beefsteak tomatoes

1. Heat outdoor grill.
2. Brush mushrooms and onion slices with 3 T oil.
3. Grill onion and mushrooms, gill sides down, 12 minutes, turning after 6 minutes, or until onion and mushrooms are crisp-tender.
4. Meanwhile brush cut sides of bread with 2 T oil.
5. Grill, cut sides down, 2 minutes or just until lightly toasted.
6. Transfer to a platter, cover with foil to keep warm.
7. Mix remaining 1 T oil, the vinegar, garlic and 1/4 t each salt and pepper.
8. Using a spatula, place an onion slice in the cavity of each mushroom and brush with vinegar mixture.
9. Top each with cheese, 3 basil leaves and a tomato slice.
10. Drizzle tomatoes with oil, if desired, and sprinkle with remaining salt and pepper.
11. Cover grill and cook 2-3 minutes or until cheese is melty and soft.
12. To serve: Place a mushroom 'burger' on each piece of grilled bread.
13. Cut a few basil leaves in thin strips and sprinkle on burgers for garnish.

portabella mushrooms, red onion, extra virgin olive oil, extra virgin olive oil, bread, balsamic vinegar, garlic, salt, ground black pepper, cheese, basil, tomatoes

Taken from www.food.com/recipe/stuffed-portabella-burgers-233398 (may not work)