If you've ever wanted that warm, steamy, deli-thin roast beef vibe at home (without leaving the couch), this is my go-to arbys roast beef recipe for doing it in a slow cooker and making it feel sandwich-shop legit. The trick is not shredding the meat into pot roast territory: we cook a lean roast gently until it's sliceable, chill it so it firms up, then shave it thin and dunk it back into a savory jus so every bite is tender and juicy. Piled onto toasted onion rolls with a swipe of horseradish mayo (and an optional quick cheddar sauce if you want to flirt with a homemade arby's roast beef sandwich moment), it's messy in the best way. This is basically how to make arby's roast beef sandwich energy at home: soft roll, hot beef, salty-sweet onion notes, and a dip cup of that broth you'll be tempted to drink straight. Bonus: it's a weeknight-friendly make-ahead because the chilling step is actually doing you a favor, not making your life harder.

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Slow-Cooked Arby's Inspired Roast Beef Sandwiches on Onion Rolls

Slow-cooker roast beef cooked for slicing, dunked in rich jus, and stacked on toasted onion rolls for a copycat arby roast beef sandwich at home.

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Prep Time 25

Cook Time 5 35

Total Time 6

Course Main Dish

Cuisine American

Servings 6

Equipment

6-quart slow cooker a 6 quart crock pot is ideal so the roast sits snugly; a Dutch oven in a low oven works too, but you'll need to watch the liquid level
Instant-read thermometer helps you nail sliceable doneness (think roast beef, not shreddable pot roast); if you skip it, use a thin knife to check tenderness and keep the cook gentle
large rimmed sheet pan or casserole dish for chilling the cooked roast so it firms up for thin slicing; a loaf pan also works in a pinch
Sharp slicing knife a long carving knife is best; an electric knife is great; a deli slicer makes it ultra-thin but is not required
Fine mesh strainer for a cleaner jus; you can also ladle carefully and leave sediment behind
Small saucepan only needed if you're making the optional cheddar sauce; microwave works, but stovetop gives smoother control

Ingredients

For the slow-cooked roast beef

3 pound top sirloin roast or use beef arm roast for a beefier pot-roast-style flavor; avoid heavily marbled chuck if you want deli-like slices
2 teaspoon kosher salt if using fine salt, reduce slightly
1 1/2 teaspoon garlic powder granulated garlic also works
1 1/2 teaspoon onion powder this is part of the classic fast-food roast beef vibe
1 teaspoon paprika sweet paprika for color; smoked paprika is fine if you like a little campfire note
1/2 teaspoon black pepper freshly ground if possible
2 cup low-sodium beef broth or use stock; you can add more later if you want extra dipping jus
1 cup water keeps the jus from getting too salty as it reduces and concentrates
1 tablespoon worcestershire sauce adds that savory depth that makes the broth taste like more than broth
1 tablespoon soy sauce optional, but it gives a deli-style umami boost; use tamari if gluten-free
1 yellow onion sliced into thick rounds to flavor the jus; it's not meant to be the star

For the sandwiches

6 onion roll store-bought is perfect; brioche bun works if you cannot find onion rolls
2 tablespoon unsalted butter for toasting; swap with mayo for extra browning if you like
1/2 cup prepared horseradish drained; mix into mayo for a quick sauce, or serve plain
1/2 cup mayonnaise or use sour cream for a tangier spread

Optional quick cheddar sauce (for a beef-and-cheddar style)

2 tablespoon unsalted butter salted is fine, just taste before adding more salt
2 tablespoon all-purpose flour this thickens the sauce; for gluten-free, use cornstarch slurry instead
1 cup whole milk 2% works; half-and-half makes it richer
6 ounce sharp cheddar cheese shredded; pre-shredded works but melts smoother if you shred it yourself
1/4 teaspoon garlic powder optional
1/4 teaspoon kosher salt taste and adjust depending on your cheese

Instructions

Season and set up the slow cooker

Pat the roast dry with paper towels (dry surface = better flavor). In a small bowl, mix salt, garlic powder, onion powder, paprika, and black pepper. Rub the seasoning all over the top sirloin roast, pressing so it adheres.
Scatter the sliced onion in the bottom of a 6 quart slow cooker. Pour in beef broth, water, worcestershire sauce, and (if using) soy sauce. Set the seasoned roast on top of the onions. The liquid should come partway up the sides, not fully submerge the meat.

Slow cook until sliceable (not shreddable)

Cover and cook on low for 330 minutes. You are aiming for roast beef you can slice thin, so check doneness with an instant-read thermometer. For a tender, sliceable result, target about 135-145F in the thickest part. If you prefer more well-done (still sliceable), go to 150F, but stop before it turns into pull-apart pot roast.
Transfer the roast to a rimmed sheet pan or casserole dish. Tent loosely with foil and let it cool for 15 minutes so the juices settle.

Make the jus and chill the beef for thin slicing

Strain the cooking liquid into a bowl or measuring pitcher (discard onion slices or save them for another use). Skim excess fat if desired. Taste the jus and adjust: if it tastes flat, add a small splash of worcestershire; if it is too strong, dilute with a little water.
This is the not-so-secret secret for a homemade arby's roast beef sandwich texture: chill the roast. Refrigerate the roast on the sheet pan until it is firm enough to slice very thin, about 45 minutes. If you are making ahead, cover and chill overnight.

Slice, rewarm, and build the sandwiches

Warm the strained jus in a saucepan over medium heat until steaming but not boiling. While it warms, slice the chilled roast as thinly as you can across the grain. If you have a deli slicer, this is the moment to show off; otherwise, use a long sharp knife and take your time.
Add the sliced beef to the hot jus in batches and let it heat through for about 2 minutes per batch. This dunk-and-warm step gives you that classic juicy deli roast beef vibe even if your slices are not paper thin.
Split the onion rolls. Spread a thin layer of butter on the cut sides and toast in a skillet over medium heat until golden, about 3 minutes.
Stir together mayonnaise and prepared horseradish for a quick horseradish mayo (or serve them separately if you like to control the heat). Spread on the toasted rolls. Pile on a generous mound of the hot, jus-soaked beef and serve with extra warm jus on the side for dipping.

Optional quick cheddar sauce

In a small saucepan over medium heat, melt butter. Whisk in flour and cook for 1 minute to remove the raw flour taste. Slowly whisk in milk until smooth and slightly thickened, about 3 minutes.
Reduce heat to low. Add cheddar a handful at a time, whisking until melted and smooth. Season with garlic powder and salt. Drizzle over the beef before closing the sandwiches if you want a beef-and-cheddar style finish.

Pairings

What to serve with these sandwiches

These sandwiches are rich, salty, and super savory, so the best sides are either crunchy, tangy, or potato-based (or all three).

Curly fries or waffle fries: Honestly, the most on-theme option. Bake or air-fry them extra crisp, then use the leftover jus as a dip for a completely unhinged but wonderful snack.
Vinegar-forward coleslaw: A mayo-heavy slaw can feel like a lot next to a buttery onion roll. I like a simple cabbage slaw with apple cider vinegar, a pinch of sugar, celery seed, and black pepper to cut through the beefiness.
Dill pickles and pickled onions: Even if you love the sandwich as-is, a pickle spear on the side keeps each bite feeling fresh. If you want to go full deli, add a few pickled pepperoncini rings.
Au jus upgrades: If you want the jus to taste more like a full roast beef gravy recipe without turning it thick, whisk in 1/2 teaspoon dijon mustard and a pinch of onion powder while warming it. For a thicker dip, stir 1 teaspoon cornstarch with 1 tablespoon cold water and whisk into simmering jus until lightly glossy.

Drinks

Cold lager or pilsner: Clean, crisp, and not too hoppy, which keeps the focus on the beef.
Iced tea with lemon: Sweetened or not, it works with the salty roast beef and the onion roll.
Sparkling water with lime: If you are doing cheddar sauce, the bubbles help keep things from feeling too heavy.

FAQs

What cut of beef works best for this arbys roast beef recipe in a slow cooker?

For deli-style slicing, go with a lean, fairly uniform roast like top sirloin roast. It stays tender but still firms up nicely when chilled, which is key for thin slicing. You can also use beef arm roast if you want a slightly more pot-roast-like beefiness, but it can be a bit more shreddable if cooked too long. A beef blade roast will taste great but usually has more connective tissue and marbling, so it tends to push you toward shredded texture instead of sandwich-shop slices.

How do I keep the beef from turning into shredded pot roast?

Two things: temperature and time. Cook on low and pull the roast when it hits about 135-145F in the center for sliceable roast beef. If you let it cruise well past that (or cook all day), the collagen breaks down and you end up with fall-apart meat. Delicious, but not the copycat arby roast beef texture. Using an instant-read thermometer takes the guesswork out.

Do I have to chill the roast before slicing?

If you want thin slices that look and feel like deli roast beef recipes, chilling is the move. Warm beef is soft and steamy, so it tears and crumbles when you try to slice it thin. A short chill firms the fat and tightens the muscle fibers so you can shave it. If you are in a hurry, you can slice it warm and keep slices thicker, then rewarm them in jus, but the texture will be closer to carved roast than sandwich-shop slices.

What are arby's roast beef sandwich ingredients at a basic level?

The spirit of it is simple: soft roll + hot roast beef + optional sauce. For this homemade version, the core is onion rolls, thin-sliced slow-cooked roast beef, and warm jus to keep it moist. From there you can add horseradish mayo (classic with roast beef) or go beef-and-cheddar style with a quick cheddar sauce.

Can I make this ahead or freeze it?

Yes, and it actually gets easier. Cook the roast, strain the jus, and chill both. Slice the beef cold, then store slices in a little jus so they stay moist. Rewarm gently in a saucepan until steaming. For freezing, freeze sliced beef with some jus in a freezer bag (press it flat so it thaws quickly). Thaw overnight in the fridge and rewarm in the jus. This is one of those homemade arby's roast beef sandwich setups that feels even more doable on a busy day when the hard part is already done.