Ingredients

• 6 hamburgers buns
• 0.25 cups butter
• 8 ounces sliced mushrooms
• 2 onions
• salt and freshly ground black pepper
• 2 pounds ground beef
• 1 , 1 ounce
• 12 slices havarti cheese
• 6 tablespoons mayonnaise

Instructions

1. 1 Preheat a large skillet over medium heat. Place hamburger bun halves, cut-sides down, in the hot skillet until lightly toasted, 2 to 3 minutes. Remove toasted buns to a plate.
2. 2 Preheat an outdoor grill for medium heat. Heat butter in a large saucepan over medium heat on the grill. Add mushrooms and onions; season with salt and black pepper and cook and stir until mushrooms are lightly browned, about 20 minutes.
3. 3 Meanwhile, mix ground beef and onion soup mix in a bowl using your hands. Form mixture into 6 hamburger patties.
4. 4 Lightly oil grill grates. Grill burgers for about 5 minutes, then flip and grill to your desired doneness. A meat thermometer inserted near the center of patties should read 180 degrees F (82 degrees C).
5. 5 Remove burgers from heat to rest for 5 minutes. Spread each bun with 1 tablespoon mayonnaise, and add burgers; divide mushrooms and onions between burgers to serve.

Nutrition per serving