Patty Melts
From Food Network Kitchens

Patty Melts are basically grilled hamburger patty sandwiches, traditionally made with rye bread and Swiss cheese. The hamburger patty is cooked first, then made into a grilled sandwich with fried onions and the Swiss cheese. Sauteed mushrooms would also be good on these.

The hamburger patty should be made thin, about 1/4-inch thick when forming.

3/4 pound ground sirloin
3/4 pound ground chuck
Kosher salt and freshly ground black pepper
1/4 cup vegetable oil
2 medium yellow onions, thinly sliced
12 slices Swiss or American cheese (about 3 ounces)
12 slices rye bread
1/2 cup unsalted butter, room temperature

Place the meat on a parchment paper-lined baking sheet and, using your hands, break it up into small pieces and combine evenly. Season the meat with salt and pepper to taste.

Divide the meat into 6 portions (about 4 ounces each). Using your hands, form each portion into a ball-shape by gently tossing it from one hand to the other. Form each portion into a thin patty, about 1/4-inch thick. Each patty should be somewhat larger than a slice of the rye bread since it will shrink when cooked.

Heat 1 tablespoon of the oil in a large cast-iron skillet over medium-heat. Add the onion, season with salt and pepper, and cook, stirring occasionally, until caramelized, about 7 minutes. Transfer the onion to a bowl.

Wipe out the skillet; return to the heat, and heat 1 tablespoon oil. Add 2 patties and saute, pressing them down so they do not get too thick and turning once, until well browned and cooked to medium, about 1 minute per side. Transfer to a plate and repeat with the remaining oil and patties.

Arrange 1/6 of the onion over one bread slice. Place 1 cheese slice over the onion and top with a patty. Top the patty with a slice of cheese and cover with a bread slice. Spread about 2 teaspoons of butter over the outside of each slice. Repeat with the remaining ingredients to make 6 sandwiches. [Some recipes use this order: bread, cheese, grilled onions, patty, 2nd layer of cheese, bread.]

Heat the cast-iron skillet over medium heat. Add 2 sandwiches and cook, turning once, until lightly browned and the cheese has melted, about 5 minutes per side. Transfer to a cutting board and repeat with the remaining 4 sandwiches. Cut sandwiches in half crosswise and serve.

6 servings