French Onion Soup Burgers offer a luxurious take on the traditional hamburger, inspired by the rich, comforting flavors of French onion soup.

1 lb ground beef

2 large onions, thinly sliced

2 tablespoons butter

1 teaspoon sugar

1/2 cup beef broth

2 tablespoons Worcestershire sauce

1 teaspoon fresh thyme leaves (or 1/2 teaspoon dried thyme)

Salt and pepper to taste

4 slices of Gruyère or Swiss cheese

4 hamburger buns

1 clove garlic, minced (optional for garlic butter buns)

Additional butter for buns

Caramelize the Onions:

In a large skillet over medium heat, melt the butter.

Add the sliced onions and sugar.

Cook, stirring occasionally, until the onions are deeply caramelized and sweet, about 20-25 minutes.

Add a splash of beef broth if the onions start to stick, to deglaze the pan.

Prepare the Burger Patties:

Season the ground beef with salt, pepper, and Worcestershire sauce.

Form into 4 equal-sized patties.

In a separate skillet or on a grill, cook the burger patties to your desired level of doneness.

Assemble the Burgers:

If desired, prepare garlic butter buns by spreading buns with a mixture of butter and minced garlic, then toasting until golden.

On each bun bottom, place a cooked burger patty.

Top each patty with a generous helping of caramelized onions and a slice of cheese.

Broil the assembled burgers for a few minutes until the cheese is melted and bubbly.

Sprinkle fresh thyme over the cheese, cover with bun tops, and serve immediately.

Choosing Quality Ingredients:
- Use high-quality ground beef with an 80/20 ratio for juiciness. Grass-fed or organic beef can further enhance the flavor.
- Gruyère cheese is ideal for its melting properties and nutty flavor, but Swiss or provolone can be good alternatives.
Caramelizing Onions:
- Caramelizing onions properly takes time. Cook them over low heat and be patient to achieve the perfect sweetness and depth of flavor. Stir occasionally to prevent burning and ensure even cooking.
Cooking the Patties:
- Whether grilling or cooking on the stovetop, aim for an internal temperature of 130-135°F for medium-rare or 140-145°F for medium. Let the patties rest for a few minutes after cooking to keep them juicy.
Toasting the Buns:
- Toast the buns with garlic butter to add an extra layer of flavor and prevent them from becoming soggy. This step enhances the overall texture and taste of the burger.
Customizing Your Burger:
- Add toppings like crispy bacon, fresh arugula, or sautéed mushrooms for additional flavors. Experiment with different cheeses and sauces to make the burger your own.
Making Ahead:
- Caramelized onions can be made in advance and stored in the refrigerator for up to 5 days or frozen for up to 3 months. This can save time when assembling the burgers.