Great Grilled Vegetable Oyster Mushrooms Sandwich

Herbed Mayonnaise,  recipe follows
Herbed Mayonnaise:
3/4 cup mayonnaise
1/2 lemon, juiced
A few drop hot sauce
1 garlic clove, crushed and skin removed
2 tablespoons thyme leaves
2 tablespoons flat-leaf parsley leaves
2 tablespoons chopped chives
Directions

Using a pastry brush, brush olive oil on the vegetable slices and the portobello mushrooms. Season them with salt and pepper. Place vegetables on a hot grill and cook until they are tender. Once vegetables are done brush sliced bread with olive oil and grill on both sides. To assemble, slice portobellos into 1/4-inch slices, spread both sides of the grilled bread with herbed mayonnaise and then top with 1 slice each of grilled vegetables and a quarter of the mushrooms, and finish off with lettuce and top with remaining piece of bread.