Arby’s Roast Beef Sandwich Recipe: Copycat Au Jus and Horsey Sauce

Recreating that iconic deli-style roast beef sandwich at home is easier than you think. This version captures the exact flavors and textures that made the original famous, from the tender sliced beef to the signature sauces.

The secret lies in slow-roasting the beef until perfectly tender, then slicing it thin for that classic deli experience. The au jus and horsey sauce complete the authentic taste, making every bite as satisfying as the restaurant version.

You’ll achieve restaurant-quality results with simple ingredients and careful technique. The beef stays juicy, the sauces add just the right tang, and the sandwich comes together beautifully.

Serve on toasted rolls for a meal that tastes just like the original. This recipe delivers the full experience without leaving your kitchen.

Ingredients for Arby’s Roast Beef Sandwich

Slow-roasted beef, bold sauces, and soft rolls recreate that deli classic at home with precision.

The beef is paramount for this copycat. Top round roast delivers the right texture—lean but tender when slow-cooked. Source from Whole Foods or Costco for consistent quality. Look for even marbling; avoid pre-cut roasts as they dry out faster. The spices (garlic powder, onion powder, thyme, rosemary) should be freshly opened—old spices lose potency and won’t give that signature Arby’s depth.

No horseradish? Freshly grated ginger adds a similar kick (use half the amount). For a milder sauce, reduce horseradish to 1 tbsp. Beef broth can be swapped with mushroom broth for a vegetarian twist, though the flavor profile shifts slightly. The rolls must be soft and sturdy—Hawaiian rolls work in a pinch if onion rolls aren’t available.

Au jus reheats well—store in an airtight container for up to 5 days. Horsey sauce keeps for 1 week refrigerated. Slice the beef just before serving to retain moisture, and toast the rolls lightly to avoid over-browning. Leftovers make killer next-day sandwiches.

Step-by-Step Instructions for Arby’s Style Roast Beef Sandwich

Master the cooking and assembly process to recreate this iconic sandwich with authentic flavor.

Step 1: Season and Roast the Beef Top Round

Preheat your oven to 325°F. Pat the 2.5 lb Beef Top Round Roast dry and rub it with 2 tsp Kosher Salt, 1 tsp Black Pepper, 1 tsp Garlic Powder, 1 tsp Onion Powder, 0.5 tsp Dried Thyme, and 0.5 tsp Dried Rosemary. Massage the spices into the meat to ensure even coverage.

Place the seasoned roast on a rack in a roasting pan. Roast uncovered for 1.5 to 2 hours until the internal temperature reaches 135°F for medium-rare. This slow cooking method preserves moisture and develops rich flavor throughout the beef.

Step 2: Prepare the Au Jus Dipping Sauce

While the beef cooks, combine 2 cups Beef Broth and 1 tbsp Worcestershire Sauce in a small saucepan. Simmer over medium heat for 10 minutes to concentrate the flavors.

Once the roast is done, transfer it to a cutting board and pour the pan drippings into the broth mixture. Skim off any excess fat, then keep the au jus warm. The sauce should have a deep, savory aroma and a rich amber color.

Step 3: Slice the Beef Thinly

Let the roast rest for 15 minutes before slicing. This allows the juices to redistribute, ensuring each bite is tender and flavorful. Using a sharp knife, slice the beef against the grain into paper-thin pieces, approximately ⅛-inch thick.

The slices should be delicate enough to fold slightly when picked up, mimicking the signature texture of the original. Keep the slices covered loosely with foil to maintain warmth and moisture as you work.

Step 4: Toast the Onion Rolls

Split the 4 whole Onion Rolls and lightly butter each half with 2 tbsp Unsalted Butter. Toast them in a skillet over medium heat for 2-3 minutes per side until golden brown.

The rolls should be warm and slightly crisp on the outside but still soft inside. This step enhances their ability to hold up to the juicy beef and sauces without becoming soggy.

Step 5: Make the Horsey Sauce and Assemble

In a small bowl, whisk together 0.5 cup Mayonnaise, 2 tbsp Prepared Horseradish, 2 tbsp Ketchup, and 1 tbsp Mustard until smooth. Adjust the horseradish to taste if you prefer a milder or spicier kick.

To assemble, layer the sliced beef on the bottom half of each roll, spoon the horsey sauce generously over the meat, and cap with the top half. Serve immediately with warm au jus on the side for dipping, ensuring each sandwich delivers the full, bold flavor experience.

Common Mistakes When Making This Dish

Overcooking the Beef

Roasting beyond 135°F internal temperature turns your beef dry and chewy. I pull mine at exactly 130°F and let it carry over to 135°F while resting. Use a meat thermometer—guessing leads to disappointment. 🌡️

Slicing Too Thick

The magic is in paper-thin slices, about ⅛-inch thick. Thicker cuts lose that deli-style tenderness. I chill the roast for 20 minutes before slicing for cleaner cuts, then let it come to room temp before serving.

Skipping the Rest

Slicing immediately after roasting lets precious juices escape. Always rest the beef for 15 minutes under foil. This step keeps the meat moist and makes assembly easier.

Weak Au Jus

Simmering the broth and Worcestershire for only 5 minutes gives bland results. Reduce it for 10-12 minutes to concentrate flavors. I add the pan drippings for extra depth.

Sauce Imbalance

Horsey sauce needs balance—2 tbsp horseradish to ½ cup mayo is perfect. Too much horseradish overpowers; too little disappears. I taste and adjust with small ½ tsp increments. 💡

Soggy Rolls

Toast the rolls just before assembly, not hours ahead. Butter them lightly—½ tbsp per half—and use medium heat for 2 minutes per side. This keeps them crisp enough to handle the juices.

Frequently Asked Questions