Portobello Mushroom Burgers

1 cup light mayonnaise
1/3 cup chopped fresh basil
2 Tablespoons Dijon mustard
1 teaspoon lemon juice
½ teaspoon salt
1/8 teaspoon freshly ground pepper
1/3 cup olive oil
2 large cloves garlic, peeled and minced
6 (¼-inch) slices purple onion
6 large Portobello mushrooms
6 hamburger buns, split
6 romaine lettuce leaves
2 large tomatoes, cut into 6 slices each

Prepare a charcoal fire on grill.

Stir mayonnaise, basil, mustard, lemon juice, salt and pepper together; set aside.

Remove stem from mushrooms; clean. Place wooden skewers through onion slices to hold rings in place. Whisk together oil and garlic; brush on both sides of mushrooms and onions.

Grill onions and mushrooms, covered with grill lid, over medium-high heat four minutes on each side or until tender. Grill bun halves, cut side down 2 minutes or until lightly browned.

Layer 6 bottom bun halves evenly with lettuce, onion, mushroom, mayonnaise mixture, and 2 tomato slices; top with remaining bun halves. Yield: 6 servings.