1Brush grill rack with vegetable oil. Heat coals or gas grill for direct heat.
2Mix turkey, mayonnaise and blue cheese. Shape mixture into 6 patties, about 3/4 inch thick.
3Cover and grill patties 4 to 5 inches from medium heat 15 to 20 minutes, turning once, until thermometer inserted in center of patties reads 165°F. Serve on buns with onion slices.