Preheat grill pan to high.
Place the meat in a bowl. Cut the onion in half. Grate half the onion into the meat using the small grate on a box grater. Chop and reserve the other half onion. Add Worcestershire, chipotles and sauce and grill seasoning to burgers. Drizzle a little extra-virgin olive oil over the bowl and mix meat. Score the meat into 4 sections. Make 3 mini-burgers, each 3 inches wide, 1-inch thick, from each half-pound of meat.
Heat a small sauce pot over medium heat. Add extra-virgin olive oil and garlic. Cook garlic 2 to 3 minutes then add sugar and vinegar, cook 2 minutes more and stir in tomatoes. Season sauce with salt and pepper and allow it to reduce 5 to 6 minutes more.
Grill meat 2 to 3 minutes on each side and top with cheese, if you like.
Place burgers on buns and top with raw chopped onions and warm fire roasted ketchup and serve.
