Winner of the New York State Beef Council's Best Burger in New York City award in 2012 and 2013, this variation of a Juicy Lucy is the real deal.
In a small sauté pan over medium heat, add the vegetable oil and the thinly sliced onions. Cook the onions down until golden brown, about 15 minutes, seasoning with salt and pepper.
Divide the ground beef into two 5-ounce patties and press them down so that they're nice and thin. Add 1 slice of cheese on each burger patty, and top with a few slices of onion and the bacon. Seal the 2 patties together, pressing along the edges to make sure they pressed together well.
Preheat the oven to 350 degrees.
On a griddle, sear the burger on both sides, then place in the oven until cooked through, about 8-10 minutes. Remove from the oven, and let it rest for 5 more minutes before serving. Place on the brioche bun and top with lettuce and tomato.