Ingredients:
- 1 lb ground beef
- 2 large onions, thinly sliced
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 1 teaspoon sugar
- 1 teaspoon balsamic vinegar
- 4 slices Gruyère cheese
- 4 burger buns
- 1/4 cup beef broth
- Salt and pepper to taste
- Fresh thyme for garnish
Directions:
- In a large skillet, heat the olive oil and butter over medium heat. Add the sliced onions and cook, stirring occasionally, for about 15 minutes.
- Add the sugar and balsamic vinegar to the onions, and continue cooking for another 10-15 minutes until the onions are caramelized and golden brown. Remove from heat and set aside.
- Preheat the grill to medium-high heat. Form the ground beef into 4 patties, and season with salt and pepper.
- Grill the patties for about 4-5 minutes on each side, or until cooked to your desired doneness. During the last minute of grilling, place a slice of Gruyère cheese on each patty to melt.
- Toast the burger buns on the grill for about 1-2 minutes until lightly browned.
- Assemble the burgers by placing a patty on the bottom half of each bun, topping with caramelized onions, and adding a spoonful of beef broth. Garnish with fresh thyme and top with the other half of the bun.
Prep Time: 15 minutes | Cooking Time: 30 minutes | Total Time: 45 minutes
Kcal: 450 kcal | Servings: 4 servings