Begin by peeling and slicing the large yellow onion into thick half-inch rounds. Toss the onion slices with olive oil, Worcestershire sauce, and a sprinkle of Creole seasoning.

Heat a large skillet over medium-low heat and add the seasoned onion slices. Cook for about 15-20 minutes, turning occasionally, until deeply caramelized and golden brown.

While the onions are caramelizing, take the ground beef and season it generously with Creole seasoning. Divide into four portions and shape each into thin patties.

Heat another skillet over high heat and add olive oil. Sear the beef patties for 2-3 minutes on each side, adding cheese on top in the last minute.

In a medium bowl, whisk together mayonnaise, relish, Dijon mustard, garlic powder, onion powder, smoked paprika, Tony Chachere's seasoning, and cayenne pepper.

To assemble the burger, place a caramelized onion round on a plate, top with a patty and drizzle sauce over it, then crown with another onion layer.

Serve immediately, with extra sauce on the side.