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The Roast Beef Sandwich is a classic American sandwich made popular by diners and chain restaurants such as Arby’s. This homemade sandwich is so delicious and fairly simple, made with slices of meaty roast beef, veggies, sauces and melted cheese. You can customize it with all your favorite toppings and can be eaten hot or cold.
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Leftover Roast Beef Sandwich

This recipe takes your leftover roast beef sandwich and elevates it to restaurant quality! Use a sturdy bun, fresh toppings, and an Arby’s inspired sauce for a real treat!
Total Time5 minutes
Servings: 6
Author: Izzy

Ingredients

  • 1 red onion sliced into rings
  • 2 teaspoons olive oil
  • 1 tablespoon balsamic vinegar
  • 2 tablespoons creamed horseradish
  • ¾ cup mayonnaise see note
  • ¾ cup sour cream see note
  • 2 tablespoons mustard Dijon or yellow
  • 6 kaiser rolls or similar buns
  • 1 pound leftover roast beef sliced
  • 6 slices provolone cheese
  • 1 cup arugula or microgreens
  • 1 large tomato sliced
  • salt and pepper to taste

Instructions

  • Place a large skillet over medium heat. Add the oil and onions. Sauté for 10 to 12 minutes stirring regularly, adding the balsamic vinegar halfway through. Once the onions are nicely brown and caramelized, remove from heat.
  • In a medium bowl, mix together the horseradish, mayo, sour cream and mustard. Set aside.
  • Set up an assembly station by laying out the roast beef, cheese slices, arugula, sliced tomato, onions, sauce and buns.
  • Preheat the oven or griddle to 350°F. Brush the buns lightly with olive oil. Then put them in the hot oven or griddle for 2 to 3 minutes.
  • Spread the horseradish cream sauce onto the bottom buns. Sprinkle on some arugula or greens. Add several slices of roast beef followed by some salt and pepper. Layer on the caramelized onions, cheese, tomatoes and a few more greens. Add the tops of the buns and serve.