In a medium bowl, combine the ground turkey with sea salt, black pepper, garlic powder, and onion powder until just incorporated.
Form the mixture into one large patty, pressing a small indent in the center with your thumb to ensure even cooking.
Heat the olive oil in a non-stick skillet over medium-high heat until shimmering.
Place the turkey patty in the skillet and cook for 5-6 minutes per side, or until the internal temperature reaches 165°F and the exterior is golden brown.
While the patty cooks, wash and dry the butter lettuce leaves and slice the tomato, red onion, and avocado.
Lay the lettuce leaves flat and spread the Dijon mustard across the center of each.
Place the cooked turkey burger onto the lettuce, top with tomato, onion, and avocado, then wrap the lettuce tightly around the filling.