In a large mixing bowl, combine the turkey mince, fresh breadcrumbs, egg yolk, grated cheddar cheese, chopped jalapeño, chives, garlic powder, oregano, salt, and pepper. Mix until just combined.

With damp hands, divide the mixture into four portions and shape them into patties, about ¾ inch thick.

Preheat your grill to medium-high heat (375°F to 400°F). Prepare burger buns by splitting them in half.

Grill the patties for 5–7 minutes per side until golden brown and reach an internal temperature of 165°F (71ºC).

Toast the split burger buns on the grill for 1–2 minutes until lightly toasted.

Assemble the burgers by spreading mayo on the bun, adding lettuce, a grilled patty, cheese, tomato, and onion.

Serve immediately while warm, with your choice of sides.