French Onion Soup Burgers

In a mixing bowl, combine ground beef, French onion soup mix, and breadcrumbs. Mix until well combined.
Divide the beef mixture into 4 equal portions and shape each portion into a patty.
Preheat a skillet or grill over medium-high heat. Brush the burgers with a little cooking oil.
Cook the burgers for 4-5 minutes on each side, or until they reach your desired level of doneness. During the last minute of cooking, top each burger with a slice of Swiss cheese and let it melt.
While the burgers are cooking, in a separate skillet, melt butter over medium heat. Add thinly sliced onions and cook, stirring occasionally, until caramelized, about 15-20 minutes.
Once the onions are caramelized, pour in beef broth and bring to a simmer. Let it cook for another 5 minutes.
Season the onion broth with salt and pepper to taste.
To assemble the burgers, place each cooked patty on a burger bun. Top with a generous spoonful of caramelized onions and drizzle with some of the onion broth.
Serve hot and enjoy these flavorful French Onion Soup Burgers!