Description
This Prime Rib Sandwich features thinly sliced leftover prime rib layered with sweet caramelized onions, creamy horseradish sauce, and melted provolone cheese on a crisp baguette. Topped with peppery baby arugula, this sandwich combines savory, tangy, and fresh flavors perfect for a satisfying lunch or dinner.
Ingredients
For the Caramelized Onions
- 4 tablespoons unsalted butter
- 1 tablespoon white balsamic vinegar
- 1/2 teaspoon kosher salt, divided
- 1/4 teaspoon black pepper, divided
- 1 large onion, thinly sliced (implied for caramelized onions)
For the Sandwich
- 1 pound leftover prime rib, thinly sliced and fat removed
- 1 large baguette, sliced in half lengthwise and cut into about 4 sections
- 4 – 6 slices provolone cheese
- 2 ounces baby arugula
- 6 tablespoons creamy horseradish sauce
- Additional kosher salt and black pepper, to taste
Instructions
- Caramelize the Onions: Melt the butter in a large skillet over medium-low heat. Add thinly sliced onions with a pinch of salt. Cook, stirring occasionally, for 30 to 40 minutes until the onions are deeply golden brown and soft. This slow cooking process develops the rich flavor needed for the sandwich.
- Season the Onions: Stir in the white balsamic vinegar and black pepper. Season with additional salt to taste. Cook for another 2 to 3 minutes to blend flavors, then remove from heat and set aside.
- Reheat the Prime Rib: If the prime rib is cold, warm it gently either by heating in a pan over low heat or wrapping it in foil and placing in a preheated 300°F oven for about 10 minutes to preserve tenderness and flavor.
- Prepare the Baguette: Slice the baguette lengthwise and cut it into 4 sandwich-sized sections. Arrange the baguette halves on a baking sheet for assembly.
- Assemble the Sandwiches: Spread creamy horseradish sauce evenly on both halves of the baguette. Layer the reheated prime rib slices over the sauce. Season with salt and pepper if desired. Top the meat with the caramelized onions.
- Add Cheese and Broil: Place 1 to 1.5 slices of provolone cheese on top of the onions for each sandwich. Place the open-faced sandwiches under a broiler for 2 to 3 minutes or until the cheese is melted and bubbly. Watch carefully to prevent burning.
- Finish and Serve: Remove the sandwiches from the oven. Top each with baby arugula and season arugula with a pinch of kosher salt and black pepper. Add additional horseradish sauce if desired. Close the sandwiches, serve, and enjoy!
- Store Leftovers: Keep any leftover sandwiches in an airtight container in the refrigerator for up to two days for best freshness.
Notes
- Slow caramelization of onions is essential to develop a deep, sweet flavor—do not rush this step.
- Reheating the prime rib gently prevents drying out the meat and keeps it tender.
- Watch the sandwiches closely under the broiler to avoid burning the cheese or bread.
- This sandwich is best enjoyed freshly assembled but can be stored refrigerated for up to two days.
- Adjust horseradish sauce and seasoning to your taste preferences.
- Prep Time: 10 minutes
- Cook Time: 45 minutes
- Category: Sandwich
- Method: Broiling
- Cuisine: American
