- 1 pound ground beef sirloin
- 1 pound ground beef chuck
- Salt and freshly ground black pepper to taste
- Vegetable oil cooking spray
- Six 1/2-inch-thick slices white onion
- Canola oil
- 3 ounces blue cheese, cut into 6 slices or crumbled
Combine the beef and salt and pepper in a bowl. Using your hands, mix well. Form into 6 patties. Refrigerate until ready to grill.
Prepare a charcoal or gas grill: Lightly spray the grill rack with vegetable oil cooking spray. Light the coals or heating elements, and let them burn or heat until hot.
Brush the onion slices with oil and season each with salt and pepper. Grill on the outer edge of the grill for 5 or 6 minutes until the onions begin to soften. Turn and grill for 8 to 9 minutes on the other side, until tender and lightly browned. Lift from the grill, set aside, and keep warm.
Grill the burgers 3 to 4 minutes on first side for medium-rare. Flip burgers and place a slice of cheese or crumble about 1/2 ounce cheese on top of each. Grill the burgers, covered, for 3 to 4 minutes longer, until the cheese melts and the burgers are medium-rare. Top with the onions and serve.