Swiss Mushroom Burgers

• 1 1/4 pounds ground beef (preferably chuck)
• Kosher salt and freshly ground pepper
• 2 teaspoons extra-virgin olive oil, plus more for brushing
• 1 small red onion, halved and thinly sliced
• 1 8 -ounce package sliced mixed mushrooms
• 1 tablespoon Worcestershire sauce
• 1/4 cup ketchup
• 2 teaspoons dijon mustard
• 4 thin slices gruyere cheese
• 4 sesame buns, split and toasted
• Boston or Bibb lettuce, for topping
• Potato chips and/or pickles, for serving (optional)

1. Preheat the broiler and line the bottom of a broiler pan with foil.
2. Lightly mix the beef with 1 teaspoon salt and 1/2 teaspoon pepper in a large bowl.
3. Gently form into 4 patties, about 3/4 inch thick.
4. Arrange on the prepared pan and brush both sides with olive oil.
5. Broil until browned, about 4 minutes per side for medium rare.
6. Meanwhile, heat 2 teaspoons olive oil in a large skillet over medium-high heat.
7. Add the onion and cook, stirring, 2 minutes.
8. Add the mushrooms and cook 2 more minutes.
9. Add the Worcestershire sauce and cook until the vegetables are tender, about 2 more minutes.
10. Season with salt and pepper and remove from the heat.
11. Combine the ketchup and mustard in a small bowl and set aside.
12. Top each patty with one-quarter of the mushroom mixture and 1 slice cheese.
13. Return to the broiler to melt the cheese, about 1 minute.
14. Spread the buns with the ketchup mixture; sandwich with the patties and some lettuce.
15. Serve with chips and/or pickles.
16. Per serving: Calories 544; Fat 31 g (Saturated 13 g); Cholesterol 110 mg; Sodium 1,143 mg; Carbohydrate 30 g; Fiber 2 g; Protein 38 g
17. Photograph by Antonis Achilleos

ground beef, kosher salt, extravirgin olive oil, red onion, mushrooms, worcestershire sauce, ketchup, mustard, thin slices gruyere cheese, sesame buns, bibb lettuce, pickles

Taken from www.foodnetwork.com/recipes/food-network-kitchens/swiss-mushroom-burgers-recipe.html (may not work)