Summer Chicken Burgers

Step 1
Combine sliced avocado and lemon juice in a small bowl. Add water to cover; set aside.

Step 2
Preheat an outdoor grill for high heat and lightly grease the grate.

Step 3
Heat butter in a large heavy skillet over medium-high heat. Saut? onions until browned and caramelized; set aside.

Step 4
Season chicken with salt and pepper. Place on grill and cook until no longer pink and juices run clear, about 5 minutes on each side. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).

Step 5
Place buns on grill just long enough to toast them.

Step 6
Spread buns with mayonnaise to taste, then layer with chicken, caramelized onion, provolone, and avocado.