01 - In a large bowl, mix ground turkey, onion, garlic, Dijon mustard, Worcestershire sauce, salt, pepper, and parsley until just combined without overworking.
02 - Shape the mixture into 4 equal patties, slightly larger than the buns.
03 - Heat olive oil in a large skillet or grill pan over medium heat.
04 - Cook patties for 5 to 6 minutes per side until golden and thoroughly cooked; internal temperature should reach 165°F.
05 - Place a slice of cheddar cheese on each patty during the last minute of cooking and cover to melt.
06 - Toast the burger buns until golden.
07 - Spread mayonnaise and ketchup on buns if desired. Layer lettuce and tomato on the bottom half, add the turkey patty with melted cheese, top with pickle slices, then cover with the top bun.
08 - Serve immediately while warm.