Lucinda and her son make garlic- and sage-infused turkey burgers with an extra-special sauce.
For the turkey burgers: Arrange 10 (4-inch) parchment squares on a tray. Gently mix together turkey, cheese, parsley, sage, garlic, 2 teaspoons salt, and 1 teaspoon pepper. Shape meat into 10 (3-ounce) patties (3 1/2 inches in diameter and 1/2 inch thick). Transfer patties to parchment.
For the beef burgers: Shape meat into 10 patties (see turkey burger instructions above).
Refrigerate patties for at least 1 hour.
Heat grill to medium-high; brush grates with vegetable oil.
Cook the turkey burgers: Brush tops with olive oil. Flip burgers onto grill, peeling off paper. Grill for 3 minutes. Brush tops with olive oil. Flip, and grill until cooked through, about 2 minutes more.
Cook the beef burgers: Season burgers with salt and pepper. Grill for 4 minutes. Flip, and grill until cooked through, 2 to 3 minutes more (6 minutes total for medium-rare, 7 minutes total for medium).
To serve burgers: Brush buns with butter, and grill until browning around edges, about 30 seconds. Sandwich burgers between buns, garnished with desired toppings.