Pre-heat oven to 400 degrees.
Cut sweet potatoes into wedges or slices as desired. Toss with olive oil and 1 tsp of Flavor God seasoning. Arrange in a single layer on a baking sheet. Bake for 10 minutes, flip and continue cooking for another 10-15 minutes.
Add ground turkey, grated zucchini, breadcrumbs, egg, 1/2 cup chopped onion, and remaining Flavor God seasoning to a large bowl. Mix until combined, then form 4 patties.
Grill turkey burgers until cooked through, about 10-12 minutes (I grilled mine on a George Foreman for 11 minutes at 425 degrees).
Add sliced onions to a hot, non-stick pan. Toss and continue cooking down until onions are caramelized. Add a couple tablespoons of water if needed to keep the onions moist toward the end of cooking.
Serve turkey burgers on lettuce leaves with caramelized onions and BBQ sauce.