In a large mixing bowl, combine the ground turkey, chopped onion, breadcrumbs, mayonnaise, beaten egg, minced garlic, Worcestershire sauce, salt, and pepper. Mix gently with your hands until just combined - be careful not to overmix.

Divide the mixture into 6 equal portions and shape into patties about ¾-inch thick. Use your thumb to make a slight indentation in the center of each patty - this helps them cook evenly and prevents bulging.

Preheat your grill to medium-high heat (about 375°F). Brush the grill grates with oil to prevent sticking.

Place the patties on the grill and cook for 5-6 minutes per side, or until they reach an internal temperature of 165°F. Avoid pressing down on the burgers while cooking to keep them juicy.

During the last minute of cooking, toast the brioche buns on the grill until lightly golden.

Remove the burgers from the grill and let them rest for 2-3 minutes before serving. This allows the juices to redistribute throughout the patty.

Assemble your burgers with your favorite toppings. We recommend crisp lettuce, ripe tomato slices, creamy avocado, and a spread of mayonnaise or your favorite sauce.