1. Prepare toppings: cook bacon, wash lettuce, slice tomato and avocado; set aside.
2. Preheat 3/4 of grill to medium high and season burgers with salt and pepper. Place burgers over direct heat and grill 2-3 minutes on first side; flip, baste with barbecue sauce and grill 2-3 more minutes. Flip again, baste with sauce and move patties to cool side of grill to finish cooking (should reach an internal temperature of 160°F).
3. Build burgers with bottom bun, lettuce, tomato, burger, bacon, avocado and top bun.