01 - Combine ground turkey, breadcrumbs, egg, onion, garlic, Dijon mustard, Worcestershire sauce, salt, and pepper in a large bowl. Mix gently until just combined, being careful not to overwork the meat.
02 - Shape the mixture into 4 equal-sized patties, approximately 1/2 inch thick. Make a slight indentation in the center of each patty to prevent puffing during cooking.
03 - Preheat a grill or skillet over medium heat. Lightly oil the surface to prevent sticking.
04 - Place patties on the heated surface and cook for 5–6 minutes per side. Cook until fully cooked through, reaching an internal temperature of 165°F.
05 - During the final minute of cooking, place a slice of cheddar cheese on each patty. Cover with a lid to allow the cheese to melt completely.
06 - Butter the cut sides of the burger buns. Place them on the grill or skillet cut-side down and toast until golden brown and lightly crisp.
07 - Spread mayonnaise, ketchup, or mustard on the toasted buns as desired. Layer with lettuce leaves, tomato slices, and thinly sliced red onion.
08 - Place the cheese-topped turkey patties on the prepared buns and serve immediately while hot.