Cut Ciabatta buns in half, drizzle olive oil over the top, and set aside.
In a large bowl, combine ground beef, Worcestershire Sauce, steak seasoning, garlic; mix well. Using your hands, form the hamburger mixture into two (2) hamburger patties. Place on a large plate and cover with plastic wrap; set aside until ready to grill.
Meanwhile, saute onions in large non-stick pan in olive oil until very soft and just starting to brown. Add salt and pepper to taste. Set aside.
Prepare your gill (oil hot grill to help prevent sticking). Grill the hamburger patties until a meat thermometer registers an internal temperature of at least 160 degrees F. or to your liking. Remove from grill.
This is the type of cooking and meat thermometer that I prefer and use in my cooking. I get many readers asking what cooking/meat thermometer that I prefer and use in my cooking and baking. I, personally, use the Thermapen Thermometer shown in the photo on the right. To learn more about this excellent thermometer and to also purchase one (if you desire), just click on the underlined: Thermapen Thermometer.
While the hamburger patties are grilling, place the Ciabatta buns on the grill and heat until nice grill marks form; remove from grill.
Place prepared onions on grilled ciabatta buns. Then layer lettuce leaves, hamburger patties, tomato slices, and more onions if desired.
Makes 4 servings.