1 ripe avocado, sliced
1 tablespoon lemon juice
1 tablespoon butter
1 large Vidalia onions, sliced into rings
4 boneless, skinless chicken breast halves
salt and pepper to taste
4 hamburger buns
4 tablespoons mayonnaise
4 slices provolone cheese
In a small bowl, combine sliced avocado and lemon juice. Add water to cover; set aside. Preheat an outdoor grill for high heat and lightly oil grate.
Heat butter in a large heavy skillet over medium-high heat. Saute the onions until browned and caramelized; set aside.
Season the chicken with salt and pepper. Place on grill, and cook until no longer pink and juices run clear, about 5 minutes on each side. Place buns on grill just long enough to toast them.
Spread buns with mayonnaise to taste, then layer with chicken, caramelized onion, provolone and avocado.