Prime Rib Sandwich with Horseradish Cream and Au Jus
Think of this as the sandwich that turns a prime rib into its very own victory lap. Thin slices of tender beef, a sharp and creamy horseradish sauce, and a blanket of melted provolone all piled onto a crusty roll, then dunked straight into warm au jus.
Whether you have a few slices of holiday roast left in the fridge or you grab some rare roast beef from the deli, this one delivers. It feels like a steakhouse lunch you can pull together in half an hour flat.
What Makes This Sandwich So Good
Prime rib is already rich and deeply beefy. A tangy horseradish cream cuts right through that richness, so every bite stays bright instead of heavy. You get juicy meat, a little crunch from the toasted roll, and that salty, beefy broth clinging to the crust.
The cheese matters too. Provolone melts into a soft layer that holds everything together without tasting sharp or overpowering. I keep the horseradish sauce recipe the same no matter what, because the balance of creamy, tangy, and a little heat just works.
It is also one of the most forgiving leftover makeovers out there. Because the meat is already cooked, all you are doing is building layers and sliding it under the broiler until the cheese gets bubbly and the edges of the bread turn golden.
Ingredients
- 1/2 cup sour cream: full-fat gives the sauce its body, but light works in a pinch
- 2 tbsp prepared horseradish: use the refrigerated kind for the cleanest bite, not the creamy “horseradish sauce” in the condiment aisle
- 1 tbsp mayonnaise: pulls everything into a smooth, spreadable texture
- 1 tsp Dijon mustard: adds a little sharpness behind the horseradish
- 1 tsp Worcestershire sauce: deepens the beefy flavor
- 1/4 tsp kosher salt: adjust to your taste and broth saltiness
- 1/4 tsp black pepper: fresh cracked is best
- 1 tbsp unsalted butter: for the onions and the meat
- 1 large yellow onion, thinly sliced: gets soft and sweet fast on the stovetop
- 4 crusty hoagie rolls or ciabatta rolls: soft centers, sturdy enough to hold the jus
- 4 slices provolone cheese: mild and melty; Swiss is the other classic choice
- 1 lb cooked prime rib, sliced thin against the grain: fridge-cold slices work perfectly here
- 1 cup beef broth: or leftover pan drippings whisked with a little butter
Variations and Swaps
- Use Swiss cheese instead of provolone: a little nuttier, still melts beautifully
- Add sautéed mushrooms: cook them in the same pan after the onions for an earthy layer
- Swap the bun: a split baguette or sturdy kaiser roll both hold up to dipping
- Make it spicy: stir a half teaspoon of hot English mustard into the horseradish sauce
- Skip the horseradish: stir together equal parts sour cream and grainy Dijon with a tiny splash of Worcestershire for a milder sauce
- Use leftover au jus: if you saved the pan drippings from the roast, whisk in a little butter and warm it gently; no broth needed
If you have extra steak or roast beef instead of prime rib, try a Philly-style loaded roast beef sandwich next time.
How to Make Prime Rib Sandwiches
Step 1: Whisk the Horseradish Sauce
In a small bowl, combine 1/2 cup sour cream, 2 tablespoons prepared horseradish, 1 tablespoon mayonnaise, 1 teaspoon Dijon mustard, 1 teaspoon Worcestershire sauce, and the 1/4 teaspoon each salt and pepper. Stir until the sauce is completely smooth. Give it a taste and add a pinch more horseradish if you like a stronger kick.
Pop the bowl into the fridge while you tackle the onions. The flavors marry together and the sauce thickens just a little more, making it easier to spread over the warm rolls later.
Step 2: Sauté the Onions
Warm 1/2 tablespoon of the butter in a medium skillet over medium heat. Toss in the sliced onion and a small pinch of salt, then cook, stirring every minute or two, until the onions go glossy and turn a deep golden brown. That takes about 8 to 10 minutes.
You are not aiming for fully caramelized jammy onions here, just soft with some sweet browned edges. The pan should smell deeply savory and a little sweet. Scrape the onions onto a plate and set them aside.
Step 3: Toast the Rolls
Move an oven rack so it sits about 6 inches from the broiler and turn the broiler to high. Split each roll open and lay them cut side up on a baking sheet. Slide them under the broiler for 1 to 2 minutes, just until the cut faces turn light golden and feel dry to the touch.
Keep your eyes on them. Broilers go from toasted to burnt in seconds, so check every 30 seconds after the first minute. Pull the rolls out but leave the broiler on.
Step 4: Warm the Prime Rib
In the same skillet you used for the onions, melt the remaining 1/2 tablespoon butter over low heat. Lay the sliced prime rib in an even layer. After about 1 minute, give the meat a gentle toss and cook just until it loses its fridge chill, roughly 1 more minute for thin slices.
You are warming, not cooking. If the meat sizzles hard or starts to brown, lower the heat. Overcooking here will make those perfect slices turn dry, so pull them off as soon as they feel warm to the touch.
Step 5: Broil and Serve the Sandwiches
Spread the horseradish sauce generously onto both cut sides of each toasted roll. Pile a quarter of the warm prime rib onto the bottom half, drape the sautéed onions over the meat, and lay a slice of provolone on top. Place the open sandwiches back onto the baking sheet and broil for about 2 minutes, until the cheese is fully melted and the edges of the bread get crisp and dark gold.
In the last 30 seconds, set the top halves of the rolls onto the sheet, cut side up, to warm through. Slide the sheet out, close the sandwiches, and slice each one in half on a sharp diagonal. Pour the beef broth into a small saucepan and warm it over low heat while the sandwiches broil, then spoon it into small ramekins for dipping. Serve the sandwiches hot with the au jus right alongside.
Small Tips for the Best Prime Rib Sandwich
- Slice the prime rib cold: straight from the fridge you will get much thinner, cleaner cuts than at room temperature. Warm the slices gently after.
- Keep the heat low when warming the meat: a hot pan dries the beef out faster than you think. Low and just until it loses the chill.
- Toast the bread: this is the difference between a sandwich that sogs out and one that holds its crunch all the way through the last dip.
- Use refrigerated prepared horseradish: the bottled shelf-stable kind can taste flat and muddy. The fresh jars in the dairy aisle give you that sharp, clean heat.
What to Serve with Prime Rib Sandwiches
A handful of peppery arugula dressed with lemon and olive oil cuts through the richness of the cheese and beef. If you want something hot, salty oven fries or crispy potato wedges feel right next to the jus. And a cold lager or a hoppy ale stands its own against the horseradish.
Frequently Asked Questions
Can I use deli roast beef instead of prime rib?
Yes, but look for rare roast beef sliced thick from the deli counter. It will not have quite the same tenderness, but a gentle low-heat warm-up keeps it from turning tough.
My prime rib is already seasoned. Do I need to add anything extra?
No. The horseradish sauce and onions bring plenty of flavor. Skip any extra salt or pepper on the meat itself, and taste the sauce before you add more salt.
How far in advance can I prep the parts?
The horseradish sauce can be made a day ahead and kept in the fridge. The onions can be sautéed and stored, then rewarmed. But toast the bread, warm the meat, and broil the cheese just before you plan to eat so the sandwich stays crisp.
Can I make this sandwich without a broiler?
A toaster oven or a covered skillet with a lid works too. In a skillet, assemble the sandwich open-faced, cover, and let the trapped heat melt the cheese over low heat for a few minutes.
Prime Rib Sandwich Recipe
Ingredients
Method
- Whisk the sour cream, horseradish, mayonnaise, Dijon, Worcestershire, salt, and pepper in a small bowl until smooth. Refrigerate.
- Melt half the butter in a skillet over medium heat. Sauté the onion with a pinch of salt until soft and golden, about 8 to 10 minutes. Set aside.
- Heat the broiler and position a rack 6 inches from the heat. Split the rolls, place them cut side up on a baking sheet, and broil 1 to 2 minutes until lightly toasted.
- Melt the remaining butter in the same skillet over low heat. Add the sliced prime rib and warm gently for about 2 minutes, stirring once, just until no longer cold.
- Spread the horseradish sauce on both cut sides of each roll. Layer the warm prime rib, onions, and a slice of provolone on the bottom halves. Broil open-faced about 2 minutes until the cheese melts and edges crisp. Warm the beef broth in a small saucepan. Close the sandwiches, slice on a diagonal, and serve with small bowls of warm au jus.
