Savory French Onion Soup Burgers Recipe: Bistro Flavor at Home - Dave's Grill

Ingredients

• 1 lb (450 g) ground beef (80/20 for juiciness)
• 4 slices Gruyere or Swiss cheese
• 2 large onions, thinly sliced
• 2 tablespoons unsalted butter
• 1 tablespoon olive oil
• 1 teaspoon sugar
• ¼ cup beef broth
• ½ teaspoon salt
• ¼ teaspoon black pepper
• 1 teaspoon garlic powder
• ½ teaspoon onion powder
• 1 tablespoon Worcestershire sauce
• 4 brioche buns
• 2 tablespoons Dijon mustard (optional)
• 2 tablespoons mayonnaise (optional)
• Fresh thyme or parsley (optional, for garnish)