Gently mix all patty ingredients in a bowl; do not overwork.
Form 4 patties (1-inch thick) and press a thumbprint into the center.
Chill patties in the fridge for 20 minutes.
Preheat grill to medium-high and oil the grates.
Grill for 5 mins; flip and grill another 4–5 mins until internal temp is 165°F.
Add cheese in the last 2 mins of cooking.
Rest for 5 mins before serving on toasted buns.
Notes
Use the grated onion trick—it is the single best way to prevent dry turkey.Do not press the burgers with a spatula while cooking.Keep the meat cold until the moment it hits the hot grill.Pair with a tangy sauce to complement the lean meat.Great for meal prep as they stay moist when reheated carefully.