01 -
Slice the yellow onion thinly. Heat olive oil in a frying pan over medium heat. Add sliced onions and cook, stirring occasionally, until deep golden and caramelized, about 20 to 30 minutes.
02 -
In a medium bowl, combine ground beef, onion soup mix, and Worcestershire sauce. Gently mix until just incorporated.
03 -
Divide the beef mixture into 4 equal portions. Shape each into a patty approximately 2.5 cm thick, pressing a slight dimple into the centre of each patty.
04 -
Preheat the frying pan over medium-high heat. Sear patties for 3 to 5 minutes per side. After flipping, top each patty with a slice of provolone cheese and cover pan. Cook an additional 3 to 5 minutes, or until cheese is melted and desired internal temperature is reached.
05 -
Slice brioche buns in half and lightly brush with olive oil. Toast cut sides down in a pan over medium heat until golden.
06 -
Spread dijonnaise sauce on the bottom half of each toasted bun. Place a cooked patty on top, followed by caramelized onions. Top with the remaining bun halves. Serve immediately.