This Prime Rib Sandwich is far and away the most delicious way to use up your prime rib leftovers.
Leftover prime rib will only stay good in the refrigerator for up to 4 days so it's time to get cooking!
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Why You'll Love Rib Roast Sandwiches
When it comes to leftover holiday prime rib with prime rib seasoning, there can be absolutely no wasting. You paid top dollar for that beef roast by golly; you're gonna enjoy it to the last ounce.
This leftover prime rib sandwich is the perfect vessel for doing exactly that.
Juicy prime rib thinly sliced and served on a toasty baguette with caramelized onions, 2-minute horseradish mayo, melty Provolone cheese, and bright, peppery arugula -- it's quite literally the perfect bite.
In fact, one bite of this prime rib sandwich and you will never forget it. It is the perfect balance of meaty, savory, and zingy.
This recipe works great for any leftover cut of beef or steak. Use it for beef tenderloin, ribeyes, sirloin, or even T-bones.
Prime Rib Sandwich Ingredients
- Bread | A baguette is the ideal carby vessel for rib roast sandwiches. It's prized for its ability to get crispy and perfectly toasty while maintaining a light and airy chew. Ciabatta or bolillo rolls are also great bread alternatives. We use Ciabatta for our Ciabatta sandwich and it's to die for!
- Prime Rib | Just use whatever's left of your prime rib roast and slice it as thin as possible, almost shaved. Think deli-meat thin. This is best done while the roast is cold; it's easier to slice this way.
- Caramelized Onions | This ingredient is optional, but oh my word! It's such a difference-maker. Slow-cooked until gorgeously golden, this ingredient adds major gourmet vibes to prime rib sandwiches, brisket sandwiches, or roast beef sandwiches. A sweet, mild onion flavor melts in your mouth--so delicious! Don't feel like cooking? Use thinly sliced red onion instead.
- Horseradish Mayonnaise | This mayo is a quick and simple way to add a little zip to your sandwiches. All you need is mayonnaise, prepared horseradish, salt, and pepper. You can also use horseradish sauce if you already have some whipped up. If you aren't a fan of mayonnaise, try whole-grain mustard instead.
- Arugula | A hearty green that can hold up to the beefy flavor of prime rib! It adds a well-rounded fresh note to the prime rib sandwich and excellent color, too.
- Cheese | Provolone is mild enough in flavor not to overpower the sandwich but strong enough in flavor to know it's there. It also is a great melting cheese. You can also use Swiss or Monterey Jack.
How to Make Leftover Prime Rib Sandwiches
Prep Your Onions | Cut the onion in half down the root, cut away the end opposite the root, and remove the paper. Cut into thin slices.
Sauté the Onions | Add the butter to a large sauce pan over medium-low heat, and as soon as it has melted, add thinly sliced onions to the pan. Cook for about 20-25 minutes, stirring occasionally.
Make the Horseradish Mayo | Add mayonnaise, prepared horseradish, salt, and pepper to a bowl and stir. Set aside until ready to use. If you want to get a little extra with the sauces, you can opt for a warm drizzle of gorgonzola or hit with a zesty spoonful of chipotle ranch dressing.
Prep the Beef | Cold prime rib will slice easier than room temperature, so as soon as you take prime rib out of the fridge, use a sharp knife to slice as thin as possible.
- Note: To reheat prime rib for sandwiches, do so in a pan on the stovetop or the microwave.
- Place the pan over medium heat and add 1 to 2 slices of prime to the pan at a time. Heat for about 1 minute on each side.
- You can also reheat in the microwave, covering beef with a damp paper towel to retain moisture. Start at 1 minute and reheat at 30-second intervals after that until warmed to your liking. How much prime rib you're reheating will determine how long it takes.
Cut the Baguette in Thirds | Cut each portion horizontally down the center. Once you have the beef and onions ready, it's time to toast the bread.
Toast the Bread | Slather it with a thick layer of room-temperature butter and lay cut side on a large pan over medium heat. Toast the bread for about 2-3 minutes or until the interior is golden to your liking.
Assemble | Cover both sides of the bread with horseradish mayonnaise, add arugula to the bottom bun, and top with sliced prime rib. Add cheese slices, and finish with a generous spoonful of caramelized onions. Add the top and take the most delicious bite you've ever had.
If you have leftover au jus sauce, heat it up and serve it on the side for an extra-decadent touch.
5 More Next-Level Sandwich Recipes
- BBQ Chicken Sandwich
- Crab Cake Sandwich
- Salmon Sandwich
- Light Shrimp Po' Boy
- Ciabatta Shrimp Sandwich
Leftover Prime Rib Sandwich
Ingredients
- ½ cup + 3 tablespoons unsalted butter, room temperature
- 2 yellow onions, halved and thinly sliced
- ⅓ cup mayonnaise
- 3 tablespoons prepared horseradish
- 1 baguette, sliced into thirds (or 5-6" long portions)
- Leftover, thinly sliced prime rib (about 3 slices per sandwich)
- 1 cup baby arugula, washed and dried
- 8-10 thin slices of Provolone cheese
Instructions
- Add a ½ cup butter to a large pan over medium-low heat, and as soon as it has melted, add thinly sliced onions to the pan. Cook for about 20-25 minutes, stirring occasionally. Remove from the stovetop as soon as the onions are golden brown and softened. Set aside.
- Add the mayonnaise and horseradish to a small bowl and sprinkle with a ¼ teaspoon of salt and a pinch of black pepper. Stir to combine and set aside.
- Place a large pan on the stovetop over medium heat. Slather it with a thick layer of the remaining butter, and lay cut side on a large pan over medium heat. Toast the bread for about 2-3 minutes or until the interior is golden to your liking.
- You can reheat the prime rib on the stovetop in same pan as you heated the bread, at the same heat level. Add a slice or two of prime rib to the pan and allow to sit for about 1 minute. Flip, and cook 1-2 minute more until warm to your liking
- Cover both sides of the bread with horseradish mayonnaise, add arugula to the bottom bun, and top with sliced prime rib. Add cheese slices, and finish with a generous spoonful of caramelized onions. Add the top bun, serve, and enjoy!
Nutrition
Caralyn @ BeautyBeyondBones says
Wow, what colorful sammies! I know a few people in my family who would flip for these!
Kelly Anthony says
Thank you, Caralyn!
Sonia says
Oh my goodness!I feel like grabbing one off the screen!
Beautifully explained can't wait to give it a try!
Elaine Benoit says
I'm serving prime rib for my NYE party and now I'm hoping there will be leftovers so I can make your delicious and delightful sandwiches! Maybe I'll buy more than I need just so I can!
Alina | Cooking Journey Blog says
Great recipe for the leftover prime rib! I think together with horseradish sauce, it is a delicious snack idea.
Beth Neels says
Horseradish sauce is perfect for these prime rib sandwiches! I don't often have extra prime rib, lol! But I am going to try it with the leftovers of our fillets that are in refrigerator from last night's dinner!
Danielle says
This is definitely a great way to use whatever you've got after a holiday celebration. In fact, this is exactly what I have been doing with any meat leftovers. Can't wait to try your sandwich now!
Jacqueline Meldrum says
I love a homemade sandwich. Nothing you buy can beat them.
Natalie says
I'm definitely saving this recipe for those days when I'll have leftovers ribs. Sounds absolutely delicious and so easy to whip up. Perfect dinner!
Pam says
We love trying different ways to use up good leftover beef and this is a great idea. Perfect for lunch or an easy, quick dinner!
Jacqueline Debono says
I love making roast beef and horseradish sandwiches. Adding rucola (arugula) is a great idea. It really goes well with beef!
Alyssa says
What a great way to use up leftover prime rib. My father is a huge prime rib fan, so I'll have to make these next time he visits.
Kelly Anthony says
Thank you, Alyssa! I'm sure he'll love it 😉
Lisa | Garlic & Zest says
This sandwich is OUTRAGEOUS! I absolutely love the way you've done it on a baguette with the creamy horseradish sauce -- MY FAVORITE!
Marlynn says
This sandwich looks amazing and is such a yummy way to use leftover prime rib!
Jenn says
I love big and hearty sandwiches and could barely wait to sink my teeth into it! What a fabulous sandwich - so flavorful - and I'm looking forward to trying some of the other combinations, too!
Cathleen @ A Taste of Madness says
I am always in the mood for a good sandwich. Especially ones that use leftovers!! This looks so good 🙂
Angela says
You definitely have to try prime rib with a horseradish sauce. It is such an amazing combination. We always have prime rib on special occasion. I can't wait to try this recipe with the leftovers.
Noelle says
I loved this recipe!! I always prefer making my own sandwiches, just great!!
Karen Kelleher says
You gave me the best idea! We always have Caesar salad with my homemade Caesar salad Dressing with Prime Rib, sooooo that’s what’s going on my sandwich!
It was awesome! I also spread
Fresh homemade horseradish root on the bread before assembling them! Soooo GOOD!
Kelly Anthony says
Oh, that sounds absolutely DIVINE!