Arbys Roast Beef Sandwich Copycat Recipe: Horsepower-Style Sauce and Charred Crust

This Arbys roast beef sandwich copycat recipe delivers the iconic taste and texture you crave—tender, slow-roasted beef with that signature charred crust and creamy Thousand Island sauce. 💛 The secret lies in the slow-roasting method, which transforms tough cuts into melt-in-your-mouth perfection while developing a deep, meaty flavor. I’ve perfected this over years of testing, ensuring every bite mimics the restaurant version down to the last detail.

The key to success starts with the beef—roasting it low and slow until it’s fork-tender, then searing it briefly to create that signature crust. This technique ensures the meat stays juicy while developing the rich, savory depth that defines Arby’s roast beef. The sauce, a creamy blend of mayonnaise, ketchup, and relish, is applied just before serving to keep it fresh and vibrant.

By the time you assemble the sandwich, you’ll have layers of flavor: the tender, caramelized beef, the crispy toasted bun, and the cool, tangy sauce all coming together in one irresistible bite. The result is a sandwich that’s so close to the original, even the most loyal Arby’s fans won’t be able to tell the difference. This recipe is designed to be your go-to for game day, lunch, or whenever a craving strikes.

Don’t worry about fancy equipment or complicated steps—this copycat recipe is foolproof and designed for home cooks. With just a few simple ingredients and a little patience, you’ll have a restaurant-quality sandwich ready in under an hour. Let’s get started on recreating that iconic flavor at home.

Ingredients for arbys roast beef sandwich copycat

Just 13 ingredients for that iconic Arby's taste—slow-roasted beef and creamy sauce magic.

The beef is everything. Top round roast is key—it's tough enough to benefit from slow roasting but breaks down beautifully. Grab it from the butcher counter if possible, not pre-sliced deli meat. Look for good marbling, but don't stress if it's not perfect. I usually buy mine from Costco when I'm making multiple sandwiches, but any grocery store carries it. For the sauce ingredients, Duke's mayonnaise and Heinz ketchup are non-negotiable—they're what gives that authentic Arby's tang. The relish? Don't even think about making your own—jarred is the way to go here. Trust me on this one.

No top round roast? Bottom round or chuck roast will work in a pinch, but you'll need to add an extra 30 minutes to the cooking time. Running low on Worcestershire? Soy sauce plus a pinch of sugar mimics the flavor profile. The sesame buns are the tricky part—most grocery stores don't carry them. Potato buns are your next best bet, or toast regular buns with a little butter. For the sauce, if you can't find sweet pickle relish, dill pickle relish at half the amount works surprisingly well. The mustard on the buns? Yellow mustard only—Dijon will throw off the balance. And if you're feeling fancy, toast the buns in the oven with a little butter for that restaurant-style crunch.

The beef keeps 3-4 days in the fridge if wrapped tightly in foil. The sauce? Make it fresh day-of—it doesn't hold up well overnight. I like to portion the cooked beef into single-serving containers so I can reheat just what I need. The buns can be toasted ahead and stored in a paper bag at room temp for up to 2 days. Pro tip: if you're making this for a crowd, double the sauce recipe and keep it chilled in a sealed container—just stir before using. The flavor actually improves after sitting for 20 minutes, giving everything time to meld.

Step-by-step instructions for Arbys-style roast beef sandwiches

Here's how to nail that iconic charred crust and tangy Horsepower sauce at home.

Preheat your oven to 325°F. Pat the 2 lb Top Round Roast Beef completely dry with paper towels—this is key for that charred crust. Rub all sides with 1.5 tbsp Kosher Salt and 1 tbsp freshly cracked Black Peppercorns (I use a mortar and pestle for that extra coarse grind).

Heat 2 tbsp Olive Oil in a Dutch oven over medium-high heat until shimmering. Add the beef and sear for 3-4 minutes per side until you get deep brown color. The goal is to create that signature charred crust that makes this sandwich so special. Transfer the beef to the oven and roast for 2-2.5 hours until the internal temperature reaches 195°F and the meat is fork-tender.

Here's the thing—don't cut into it yet. The meat needs to rest. Let it sit in the Dutch oven for 15 minutes before slicing. This resting period is what makes the difference between tough, dry beef and melt-in-your-mouth perfection. I know it's tempting to dig in right away, but trust me on this.

While the beef rests, let's make that signature sauce. In a medium bowl, combine 0.5 cup Mayonnaise, 0.25 cup Ketchup, 0.25 cup Sweet Pickle Relish, 2 tbsp Worcestershire Sauce, and 1 tbsp White Vinegar. Stir everything together until smooth and well combined.

Taste it and adjust if needed—you might want to add a pinch more salt or a splash of vinegar for that perfect tang. The sauce should be thick but still spreadable. I like to let it sit for 5 minutes before using it—this gives the flavors time to meld together. The relish adds that sweet, tangy kick that makes this sauce so addictive.

Once the beef has rested, carefully slice it against the grain into ¼-inch thick slices. You should get about 4 slices from the 2 lb roast. The grain direction is important—you'll see lines running through the meat. Cutting against these lines makes each bite tender and easy to chew.

Toast the 4 whole Arbys-Style Toasted Sesame Buns according to package instructions until they're golden brown and crispy. Spread 1 tbsp Yellow Mustard on the bottom half of each bun. Then layer with beef slices, onion wedges, and a generous spoonful of the Horsepower sauce. Top with the bun lid and press gently to hold everything together.

Here's a pro tip: if you're making these ahead of time, assemble the sandwiches without the top buns. Keep them covered in the fridge for up to 24 hours. When ready to serve, just add the buns and toast briefly to warm everything up. The beef stays juicy and the sauce maintains its perfect consistency.

Serve your copycat Arbys roast beef sandwiches immediately while the beef is still warm and the buns are crispy. The first bite should deliver that perfect combination of tender, charred beef, tangy Horsepower sauce, and crispy sesame bun. If you want to go all out, serve with some crispy onion rings on the side—just like the real deal.

This recipe makes 4 sandwiches, so you'll have leftovers if you're feeding a family. Store any extras in an airtight container in the fridge for up to 3 days. The beef actually gets better as it sits, becoming even more tender. Just reheat in the oven at 300°F for 10-15 minutes to warm through without drying out.

Dietary considerations for this arbys roast beef sandwich copycat

Gluten-Free Adaptation

For a gluten-free version, start with a gluten-free beef roast (ask your butcher for one certified gluten-free) and use gluten-free Worcestershire sauce (like Annie's or Bragg). The real challenge is the buns—opt for gluten-free sesame buns (check Udi's or Schar brands) or make your own with a gluten-free bread mix. The sauce and toppings are naturally gluten-free, so no modifications needed there. 🥩

Low-Carb Options

To make this keto-friendly, skip the buns entirely and serve the beef slices over a bed of romaine lettuce or butter lettuce leaves. Use sugar-free mustard (like Mustard Powder) and a sugar-free ketchup (such as Primal Kitchen). The sauce can stay mostly the same, but reduce the sweet pickle relish to 1 tbsp and add 1 tsp erythritol to mimic the sweetness. The result is still hearty and satisfying without the carbs. 🥗

Dairy-Free Adjustments

The sauce is already dairy-free, but the mustard on the buns might contain milk. Use dairy-free yellow mustard (like French's Dairy-Free) and check the bun ingredients for milk derivatives. For extra flavor, brush the buns with olive oil instead of butter before toasting. The beef and sauce remain unchanged, making this an easy dairy-free adaptation. 🌱

Allergen-Friendly Tips

If you're avoiding eggs (common in some mayonnaise), use vegan mayo (like Hellmann's Vegan or Just Mayo). For soy allergies, skip the Worcestershire sauce and replace it with 1 tbsp coconut aminos plus 1 tsp sugar to mimic the umami depth. Always double-check labels—some relishes and sauces contain hidden allergens. 💡

Protein-Packed Boost

Want extra protein? Add sliced hard-boiled eggs or avocado slices to your sandwich. For a high-protein sauce, mix in 1 tbsp nutritional yeast (adds 3g protein per tbsp) or 1 scoop unflavored collagen peptides (blended into the mayo). These additions keep the sandwich hearty while boosting the nutritional profile. 💪

Frequently asked questions