01 - In a large bowl, combine ground turkey, finely chopped onion, minced garlic, chopped parsley, Dijon mustard, smoked paprika, black pepper, and salt. Mix gently until just combined, avoiding overworking the meat.
02 - Divide the mixture evenly into four portions and form each into a burger patty.
03 - Heat olive oil in a grill pan or skillet over medium heat. Cook the patties for 5 to 6 minutes per side, or until fully cooked and internal temperature reaches 165°F.
04 - While cooking, combine avocado slices with lemon juice, salt, and pepper to prevent browning and enhance flavor.
05 - Lightly toast the burger buns, if desired.
06 - Spread mayonnaise on the bottom bun if using. Layer with romaine lettuce, turkey patty, tomato slices, red onion, and avocado. Top with the other half of the bun.
07 - Serve immediately alongside preferred sides.