In a mixing bowl, combine ground turkey, finely chopped onion, minced garlic, and chopped fresh parsley. Add Worcestershire sauce, Dijon mustard, salt, and black pepper. Mix gently until just combined.

Divide the turkey mixture into four equal portions, shaping each into a patty about 1 inch thick. Make a slight indentation in the center of each patty.

Preheat your grill to medium-high heat, aiming for about 400°F (200°C). If cooking indoors, preheat a skillet over medium heat and add oil.

Carefully place the turkey patties on the grill or in the skillet. Cook for 5-7 minutes on one side until golden-brown. Flip and continue cooking for another 5-7 minutes or until the internal temperature reaches 165°F (74°C).

If adding cheese, place a slice on each patty during the last minute of cooking and cover with a lid until melted.

Toast the burger buns lightly on the grill or in a toaster until golden and crisp.

Place each turkey patty onto a toasted bun. Layer with lettuce, tomatoes, and additional condiments.

Serve immediately while hot and juicy.