Strange as it may be, from time to time, we're granted the gift of leftover prime rib, and if you're looking for a little something extra to do with it post-holiday dinner, a Prime Rib Sandwich is the way to go. We all know how to assemble a sandwich -- that's the easy part, but how to make one worthy of your leftover prime rib? That may be another story.
With this recipe, that part comes easily as well. This is a stellar Leftover Prime Rib Sandwich that's quick to make and full of flavor thanks to simple ingredients like fresh arugula, Parmesan shavings, and a drizzle of creamy horseradish sauce. Not into that combo? No problem. We've got options galore for topping your prime rib sandwich, as well as tons of ideas for what to serve alongside it straight ahead!
WHAT TO PUT ON A PRIME SANDWICH?
This Prime Rib Sandwich features a combination of ingredients that work with just about any cut of beef, including beef tenderloin and leftover grilled steak, such as Ribeyes or Sirloins.
USE FRESH BAKERY BREAD
The bread used in this recipe is none other than the classic baguette, cut into hoagie-sized portions and split down the middle. Baguettes have a lovely outer crust that stands up nicely to the texture of steak, but if you'd prefer to use sliced bread, you could easily substitute that in.
Even if you aren't going to use baguette bread, I highly encourage you use fresh bakery bread for your Leftover Prime Rib Sandwiches. You can typically find a wide variety of wonderful sandwich bread at your local grocery store. Sliced sourdough, a standard home-style white loaf, and even French bread would serve as wonderful housing for your leftover prime rib and toppings.
Whether or not you choose to toast the bread is up to you, but note, toasted bread will add more flavor and a great deal of texture to your sandwich.
WHY ARUGULA FOR STEAK SANDWICHES
Arugula has a bit of a peppery note to it, which makes it ideal for pairing with red meat. Not only will the flavor of arugula stand up to steak, but the texture will hold its own as well. You can pile on as much (or as little) as you'd like to your Leftover Prime Rib Sandwich.
To move sandwich assembly along quicker, look for baby arugula with the packaged lettuces in the produce aisle. Purchasing arugula that is already washed and dried is a wonderful time-saver.
CREAMY HORSERADISH -- ALWAYS A WIN
Creamy horseradish sauce is a classic pairing for beef, and it does miraculous things for a steak sandwich. If you don't have leftover horseradish sauce from your holiday meal, you can easily whip one up in less than 5 minutes using this recipe or simply use mayonnaise in its place.
PARMESAN CHEESE (OPTIONAL)
The Parmesan cheese is optional but it adds a break of sharpness and a nice tang to a savory steak sandwich. You could also use shavings of Pecorino Romano or Machengo cheese if you'd prefer something different.
HOW TO MAKE IT YOUR OWN
You can take the bones of this Leftover Prime Rib Sandwich (i.e. the prime rib and the bread) and come up with your very own sandwich combo. Any of the following ingredients would pair well with steak. Pick and choose from this list of condiments, cheeses, and vegetables, and have fun with your very own creation!
- CONDIMENTS: Dijon Mustard, Béarnaise Sauce, Chimichurri Sauce
- CHEESE: Monterrey Jack, White Cheddar, Havarti Cheese, Gouda Cheese, Blue Cheese
- VEGETABLES: Fresh Spinach, Caramelized Onions, Sauteed Mushrooms, Sauteed Peppers (Hot or Sweet), Roasted Red Bell Peppers
HOW TO MAKE A LEFTOVER PRIME RIB SANDWICH
- Toast the bread.
- Thinly slice leftover prime rib and reheat.
- Assemble and serve.
Making Leftover Prime Rib Sandwiches is really as simple as it looks. While your bread is toasting in the oven, you'll slice your prime rib and heat it up. Then, add it to the toasted baguette, top it with the arugula, creamy horseradish sauce, Parmesan shavings (or your own creation), and dig in!
SLICING PRIME RIB FOR SANDWICHES
If your prime rib was left whole (not in slices) from the previous night's dinner, all you need to do is grab your sharpest knife, and slice the prime rib as thinly as possible for your sandwiches.
If you're left with thick leftover prime rib slices, cut those slices into bite-sized cubes and serve them in your sandwich that way. It's not ideal, but it's still going to be tasty.
HOW TO REHEAT PRIME RIB FOR SANDWICHES
To easily reheat your prime rib for sandwiches, place the prime rib on a microwavable plate and cover completely with a damp paper towel. This will help to keep the prime rib from drying out in the microwave. Then, microwave your prime rib at 30-45 second intervals (depending on how much prime rib you are microwaving), until the beef is warm to the touch.
WHAT TO SERVE WITH PRIME RIB SANDWICHES
You can make your sides for a Leftover Prime Rib Sandwich as simple or as fancy as you'd like, but mostly, it comes down to your choice of potato chips, roasted potatoes, salads, and/or soups.
- SIDE DISH POTATOES: Rosemary Roasted Potatoes, Garlic-Parmesan Smashed Potatoes, Roasted Baby Dutch Potatoes
- SIDE SALADS: Classic Wedge Salad, Caesar Salad with Creamy Parmesan Dressing, Classic House Salad
- PASTA SALAD: Antipasto Pasta Salad, Basil Pesto Pasta Salad, Greek Pasta Salad
- CUP OF SOUP: Creamy Tomato Soup, Perfect Potato and Leek Soup, Broccoli Cheese Soup

An easy prime rib sandwich featuring leftover prime rib, baguette bread, arugula, creamy horseradish sauce, and Parmesan cheese!
- 2 Baguettes
- 3 cups thinly sliced prime rib
- 2 cups arugula, washed and dried
- ½ cup shaved Parmesan
- ½ cup Creamy Horseradish Sauce
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Preheat the oven to 400°. Once heated, place the baguettes on a sheet pan and bake for 8-10 minutes, just until toasted.
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Once cool enough to handle, cut the baguette cross-ways into 5-6" portions, and slice each portion down its center lengthwise.
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Place the sliced prime rib on a microwave-safe plate and cover with a damp paper towel. Microwave at 30-second intervals until the prime rib is warm to touch.
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Divide the prime rib amongst the prepared baguettes and top with arugula, Parmesan shavings, and creamy horseradish sauce. Serve and enjoy.