2 1/2 to 3 teaspoons balsamic or red wine vinegar
1 large clove garlic, minced
Salt and pepper, to taste
1/4 cup olive oil, plus more for brushing the vegetables
2 large portobello mushrooms
1 red onion, cut into chunks
1 tomato, cut into quarters
8 slices crusty Italian bread
Fresh basil leaves

Put the vinegar, garlic, salt, pepper and 1/4 cup of the olive oil into a small jar and shake well. Set aside.

Clean the mushrooms and remove their stems. Brush all the vegetables with olive oil. Grill the mushrooms for 3 to 4 minutes on each side. Place the onion and tomato chunks on skewers and grill, turning often, until lightly charred. Cut each mushroom in half and cut the onion and tomato chunks into thin slices.

Spread a little of the vinegar mixture on each slice of bread, then top with the mushrooms, onions, tomatoes and basil leaves.