Patty Melts with Apple Slaw

http://www.foodnetwork.com/recipes/food-network-kitchens/patty-melts-with-apple-slaw.html

Total Time: 40 minutes
Prep: 15 minutes
Cook: 25 minutes
Yield: 4 servings
Level: Easy
Ingredients

1/2 small head red cabbage, shredded (about 3 cups)
1 small Granny Smith apple, cut into matchsticks
1 cup shredded carrots
2 scallions, thinly sliced
1/4 cup Dijonnaise (or Dijon mustard mixed with mayonnaise)
2 tablespoons apple cider vinegar
Kosher salt and freshly ground pepper
2 tablespoons unsalted butter
1 onion, sliced
12 ounces extra-lean ground beef sirloin
4 thin slices light Swiss cheese (about 3 ounces)
8 slices rye or marble rye bread

Directions

Make the slaw: Combine the cabbage, apple, carrot and scallions in a bowl. Add 2 tablespoons Dijonnaise and the vinegar; season with salt and pepper and toss. Set aside.

Heat 1 tablespoon butter in a large nonstick skillet over medium-high heat. Add the onion and cook, stirring occasionally, until tender and lightly browned, about 8 minutes. Season with salt and pepper. Transfer to a bowl and wipe out the skillet.

Preheat the broiler. Line a baking sheet with foil. Form the beef into four 1/4-inch-thick oval patties; season with salt and pepper. Transfer to the prepared baking sheet. Broil until cooked through, about 3 minutes. Top with the sautéed onion and cheese and continue broiling until the cheese is just melted, about 30 seconds.

Spread 4 slices bread with the remaining 2 tablespoons Dijonnaise; top with the patties and remaining bread. Melt the remaining 1 tablespoon butter in the skillet over medium-high heat. Working in batches, add the sandwiches and cook until golden, 1 1/2 minutes per side, reducing the heat as needed. Serve with the apple slaw.