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This easy prime rib sandwich is a great way to use up leftover prime rib roast! Serve thinly sliced prime rib on warm homemade ciabatta bread and top it with sweet caramelized onions, horseradish mayo, and seasoned fresh arugula. This is an easy gourmet sandwich that the whole family will love!
Quick Look at This Recipe
- Prep Time: 10 minutes
- Cook Time: 30 minutes
- Total Time: 40 minutes
- Servings: 4 people
- Dietary Info: Dairy Free (if you omit cheese)
- Method: Stovetop
- Technique: Cook the caramelized onions, then mix up the sauce. Lightly toast the ciabatta rolls and toss the greens with olive oil and lemon juice. Assemble sandwiches and enjoy.
- Flavor & Texture: This showstopping sandwich is packed with tender prime rib, cheese, caramelized onions, and zesty greens all tucked into a crispy, airy ciabatta roll.
Why You’ll Love this Recipe
If you made prime rib roast for Christmas dinner or another time during the holiday season, this prime rib sandwich is the perfect way to use holiday leftovers. You can serve it with the optional au jus sauce if you want an extra gourmet touch!
Need more ideas on what to enjoy with your leftover prime rib? Check out my ultimate recommendations in What to Serve with Prime Rib! You’ll also love my Leftover Pork Tenderloin Sandwich, Italian Beef Sandwich, and Mortadella Sandwich with Pistachio Pesto.
Made With Amore,
“This is a phenomenal sandwich, all the component come together so great, I would make prime rib just so I can make it again!”
– Daniela
Table of Contents
Ingredients for Prime Rib Sandwich
It is a great option for using leftovers from your prime rib dinner. These basic ingredients make the best prime rib sandwiches!
- Leftover Prime Rib: Use thinly sliced leftover prime rib. I highly recommend reheating this gently (or not at all) to prevent overcooking!
- Ciabatta Bread: This airy Italian bread is the perfect choice for this sandwich. The interior of the bread is soft, while the crust is thin and crispy. Use my easy ciabatta bread recipe for best results!
- Swiss Cheese: Every sandwich is better with cheese! I recommend using Swiss or provolone cheese, but blue cheese is also a delicious variation.
- Yellow Onions: You’ll caramelize these thinly sliced onions in a skillet to create a delicious, melt-in-your-mouth topping for this prime rib sandwich. Serve any extra caramelized onions with mashed potatoes for a delicious side dish.
- Horseradish Sauce: You’ll mix this with a little mayo to make a delicious sauce that brings a little zing to this prime rib sandwich!
See recipe card for full information on ingredients and quantities.
Variations & Substitutions
- Classic Philly Cheese Variation: Slice the prime rib thinly and cook it with bell peppers and onions in a skillet. Add melted provolone cheese and serve on a crusty roll for a Philly cheesesteak-inspired sandwich.
- French Dip Variation: Use a baguette and serve the prime rib sandwich au jus style. Dip the assembled sandwich into a bowl of hot beef broth before taking each bite.
- Replace horseradish sauce with Dijon mustard, sour cream, barbecue sauce, or your favorite sandwich spread. Also, try using aioli, pesto genovese, tzatziki, or my homemade burger sauce for a unique flavor.
- Don’t have leftover prime rib, but want to make this anyway? Use leftover pan-seared T-bone steak, standing rib roast, or try leftover roast beef for more of a Philly cheese steak vibe.
How to Make a Prime Rib Sandwich
See the recipe card below for the printable recipe.
- In a pan, melt butter over medium-high heat. Add the thinly sliced onions and let them get brown on the bottom. Reduce heat to medium-low and simmer until they become soft and caramelized, about 20-30 minutes.
- Season with a pinch of sugar, salt, and pepper to enhance the caramelization process. Stir occasionally.
- In a small bowl, mix horseradish sauce and mayonnaise. Adjust the ratio to your preferred level of spiciness. Set aside.
In a small bowl, toss the arugula with the olive oil and lemon juice until well coated. Set aside.
- Preheat a grill pan or skillet over medium heat. (Alternatively, you can use a toaster or oven to toast the bread.) Butter one side of each slice of bread and toast each piece until golden. Spread the horseradish-mayo sauce on the untoasted side of one slice of bread.
- Layer the thinly sliced prime rib and cheese on top.
- On the other slice of bread, spread the caramelized onions and cheese.
- Put the two slices of bread together with the spreads and fillings inside.
- Cut the sandwich in half and serve it with your favorite sides like creamy avocado coleslaw, pickles, or potato chips.
Recipe FAQs
A prime rib sandwich tastes great with simple toppings like Swiss or provolone cheese, horseradish sauce, arugula, and caramelized onions. Aim for a good mixture of color, flavor, and texture for the most appealing result.
Either Swiss or provolone cheese are great options for a prime rib sandwich! However, almost any cheese would taste great in this recipe. Try other cheeses like extra sharp cheddar, mozzarella, pepper jack, or even blue cheese.
To prevent a soggy sandwich, apply condiments and spreads to the interior of the bread slices rather than directly on the prime rib. Using a layer of greens (e.g., arugula or lettuce) can act as a barrier to keep the bread from getting too moist. Additionally, consider toasting the bread to create a more resilient surface.
Slice It: If you haven’t already, slice the meat to your desired thickness. This will help with even reheating and portion control.
Wrap It Well: Wrap the sliced prime rib tightly in plastic wrap or aluminum foil to prevent air exposure and freezer burn.
Airtight Container: Alternatively, place the wrapped prime rib slices in an airtight container. This provides extra protection against moisture and air.
Refrigerate: Store the wrapped or containerized prime rib in the refrigerator for up to 3-4 days. If you plan to keep it longer, consider freezing it.
Serving Suggestions
You’ve made a showstopping leftover prime rib sandwich, and now you need something to go with it! I highly recommend rounding out your meal with simple sides, like your favorite potato chips and dill pickles, or something a little more gourmet like smashed garlicky potatoes or a crunchy shaved Brussels sprouts salad.
My Pro Tips
Expert Tips
- Choose the Right Bread: Select a sturdy bread like a baguette or ciabatta that can hold up to the juicy meat and toppings.
- Balance Flavors: Consider the balance of flavors and textures in your sandwich. Sweet, tangy, creamy, and crunchy elements can all enhance the experience.
- Layering Matters: Arrange the ingredients thoughtfully. Place condiments and spreads on the bread’s interior to prevent sogginess, and evenly distribute the prime rib, cheese, and vegetables for each bite.
- Sauce Placement: If using au jus or another sauce, consider dipping it on the side to prevent the bread from getting too soggy.
- Toast the Bread: Toasting the bread adds a delightful crunch and helps keep it from becoming overly soft from the sandwich fillings.
Other Sandwiches You’ll Love
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Prime Rib Sandwich
Ingredients
For the Caramelized Onions
- 2 large yellow onions, thinly sliced
- 2 tablespoons butter
- salt and pepper, to taste
- 1 pinch sugar, optional
For the Horseradish Mayo
- 1-2 tablespoons horseradish sauce, adjust to taste
- 2-3 tablespoons mayonnaise
For the Arugula
- 2 cups arugula, or baby arugula
- 1 tablespoon olive oil
- 1 teaspoon lemon juice
For the Sandwiches
- 12-15 ounces leftover prime rib, thinly sliced
- 4 ciabatta rolls, or 8 slices of baguette bread
- butter or olive oil , for grilling or toasting the bread
- 4 slices Swiss cheese, or provolone cheese (optional)
For the Au Jus Dip (Optional)
- reserved juices from the cooked prime rib
- beef broth or beef stock, if needed
- salt and pepper, to taste
Instructions
Caramelize the Onions
- In a pan, melt butter over medium-high heat. Add the thinly sliced onions and let them get brown on the bottom before turning. Reduce heat to medium-low and simmer until they become soft and caramelized. This process can take 20-30 minutes. Season with a pinch of sugar (optional), salt, and pepper to enhance the caramelization process. Stir occasionally.
Prep the Sauce & Arugula
- Mix the horseradish sauce and mayonnaise in a small bowl. Adjust the ratio to your preferred level of spiciness. Set aside.
- Toss the arugula with the olive oil and lemon juice until well coated. Set aside.
Assemble the Sandwich
- Preheat a grill pan or skillet over medium heat. (Alternatively, you can use a toaster or oven to toast the bread.) Butter one side of each slice of bread and toast it until it's golden in the pan.
- Spread the horseradish-mayo sauce on the untoasted side of one slice of bread. Layer the thinly sliced prime rib and provolone or Swiss cheese on top (if using). On the other slice of bread, spread the caramelized onions.
- Put the two slices of bread together with the spreads and fillings inside. Cut the sandwich in half, and serve it with your favorite sides like coleslaw, pickles, or potato chips.
Serving with Au Jus (Optional)
- Heat the reserved juices from the cooked prime rib in a small saucepan. If needed, add a bit of beef broth to adjust the consistency. Season the au jus with salt and pepper to taste. Serve on the side with the sandwiches and use for dipping.
Notes
- Choose the Right Bread: Select a sturdy bread like a baguette or ciabatta that can hold up to the juicy meat and toppings.
- Balance Flavors: Consider the balance of flavors and textures in your sandwich. Sweet, tangy, creamy, and crunchy elements can all enhance the experience.
- Layering Matters: Arrange the ingredients thoughtfully. Place condiments and spreads on the bread’s interior to prevent sogginess, and evenly distribute the prime rib, cheese, and vegetables for each bite.
- Sauce Placement: If using au jus or another sauce, consider dipping it on the side to prevent the bread from getting too soggy.
- Toast the Bread: Toasting the bread adds a delightful crunch and helps keep it from becoming overly soft from the sandwich fillings.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
This is a phenomenal sandwich, all the component come together so great, I would make prime rib just so I can make it again!
Yes! Thanks so much!
Iโm anxious to try this recipe. Can I use the same technique but form it into rolls instead of loaves?
Yes! Absolutely
So good with leftover prime rib! The caramelized onions add the best flavor.