01 -
Heat olive oil in a large skillet over medium heat. Add the sliced onions and cook for 10-12 minutes until caramelized and golden brown. Add minced garlic and cook for an additional 1-2 minutes.
02 -
Add ground beef to the skillet, breaking it apart with a spatula. Cook until browned and fully cooked, about 5-7 minutes. Drain any excess fat.
03 -
Stir in Worcestershire sauce, soy sauce, dried thyme, salt, and pepper. Let it simmer for 5 minutes to blend the flavors.
04 -
Preheat the broiler while the mixture simmers. Lightly toast the hamburger buns under the broiler until golden brown.
05 -
Spoon the beef mixture onto the bottom half of each toasted bun. Top with shredded Swiss cheese and place under the broiler for 1-2 minutes until the cheese is melted and bubbly.
06 -
Remove from the oven, garnish with fresh parsley, and serve immediately with the top half of the bun.