- Preheat barbecue to medium-high.
- Combine mayonnaise, yogurt, mustard and roasted garlic in a bowl. Reserve. Oil barbecue rack and arrange eggplant and zucchini slices, sweet pepper quarters and mushrooms on top. Grill for about 5 minutes on each side, or until vegetables are cooked and have grill marks. Transfer to a bowl and season with salt and pepper to taste. Cover with aluminum foil and reserve.
- Place bread on barbecue rack and grill for 2 minutes on each side.
- Transfer bread to a work surface and brush one half with mayonnaise mixture. Arrange sliced cheese on top. Remove skin from peppers. Layer all vegetables on top of cheese, ending with
- Garnish with basil leaves. Top with remaining half of loaf and stick six long toothpicks into the top crust, spacing evenly, to hold bread halves and fillings in place. Cut sandwich between toothpicks into six servings. Serve with a salad of baby greens.
Tip: Prepare more vegetables for grilling and use them later in salads or sandwiches, on pizzas, in your favourite pasta recipes, or to stuff meat, poultry or fish.