2 pounds lean ground beef
1 cup crumbled feta cheese
1-1/2 Tablespoon dried oregano
salt and pepper
large red onion, peeled and cut into thin slices
large tomato, cut into thin slices
Break up beef in a large bowl. Sprinkle feta, oregano, salt and pepper and toss. Form into patties. Spray grill rack with non-stick spray. Heat grill to medium-high heat. Brush onion with oil; sprinkle with salt and pepper. Place burgers and onions on grill. Cover and cook 5 minutes. Turn; cook until onions are charred in spots and burgers are medium, about 4 minutes longer. Transfer to plate. Place buns, cut side down, on grill. Toast for about 1 minute. Place burgers on bun bottoms and top with tomato, onions, and bun top.
I served with french fries.