In a medium bowl, combine the ground turkey, egg white, garlic powder, onion powder, sea salt, and black pepper.
Gently mix the ingredients by hand until just combined, being careful not to overwork the meat which can make the burger tough.
Form the mixture into one large, thick patty of even thickness.
Heat the extra virgin olive oil in a non-stick skillet over medium-high heat until shimmering.
Place the patty in the skillet and cook for 5-6 minutes per side until the internal temperature reaches 165°F and the exterior is golden brown.
While the burger cooks, thinly slice the avocado and prepare the vegetable toppings.
Lay out the butter lettuce leaves on a plate to serve as the base.
Place the cooked turkey patty onto the lettuce leaves and spread the Dijon mustard on top.
Layer the tomato slice, red onion, and avocado slices over the patty.
Fold the lettuce leaves around the burger and serve immediately.