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This Copycat Arby's Beef & Cheddar Casserole takes the parts people remember from the sandwich and turns them into a fork-and-knife dinner. You get soft roast beef, creamy cheddar sauce, sweet-tangy red ranch, and toasted onion bun pieces that soak up just enough sauce without going mushy.
I like it when a sandwich-inspired casserole still tastes like the sandwich. That means keeping the beef tender, making the cheddar sauce smooth, and adding the red sauce in ribbons so every scoop has that familiar sharp-sweet bite.
Beef And Cheddar Lineup
The flavor depends on soft sliced beef, a sauce that tastes sharp but creamy, and buns with enough body to bake. Toast the bread cubes first so they keep their edges once the sauces hit them.
- Deli roast beef. Thin slices give the casserole the same tender bite as the sandwich and warm quickly in the sauce.
- Onion sandwich buns. They replace the sandwich roll and bake into soft centers with lightly crisp tops.
- Sharp cheddar. It brings real cheese flavor and keeps the sauce from tasting flat.
- American cheese. A small amount helps the cheddar sauce melt smooth and glossy.
- Milk and butter. They form the base of the cheese sauce and keep it pourable.
- Ketchup and vinegar. These make the red ranch-style sauce sweet, tangy, and bright.
- Worcestershire and spices. They add savory depth so the sauce does not taste like plain ketchup.
Bake The Sandwich Layers
- Toast the bun cubes. Cut the onion buns into chunky pieces and toast them briefly so the edges dry out. This keeps the casserole from turning soggy.
- Stir the red sauce. Simmer ketchup, vinegar, brown sugar, Worcestershire, and spices for a few minutes until glossy. Toss the chopped roast beef with part of this sauce.
- Make the cheddar sauce. Cook butter and flour, whisk in milk, then melt in cheddar and American cheese off the heat until smooth.
- Layer the dish. Spread half the toasted buns in the baking dish. Add saucy beef, cheddar sauce, and the remaining buns.
- Bake until bubbling. Cover for the first part of baking so the beef stays moist, then uncover to lightly crisp the top.
Copycat Flavor Without Fuss
The original Beef & Cheddar is all about contrast. The roast beef is mild, the cheddar sauce is creamy, and the red sauce cuts through with sweetness and vinegar. For a casserole, the trick is not to mix everything into one beige filling. Keep the red sauce mostly with the beef and pour the cheddar in thick ribbons. That way, each scoop has pockets of sauce instead of one flat flavor. If you want the sandwich version beside this bake, try the Homestyle Arby's Beef and Cheddar Inspired Sandwich too.
The Cheese Sauce Matters
Shredded cheddar alone can turn oily if it gets too hot. A little American cheese helps the sauce stay smooth, which is why it works so well in diner-style melts and quick cheese sauces. Keep the heat gentle after the milk thickens. If the sauce looks too thick, whisk in a splash more milk before layering. For another cozy beef bake with cheddar, the Ground Beef and Potato Casserole with Cheddar uses the same comfort-food logic in a different direction.
Best Beef To Buy
Ask the deli counter for roast beef sliced thin, but not shaved into threads. You want pieces that fold and stay juicy. Rare or medium roast beef is fine because it will heat in the casserole, but avoid very dry packaged slices if you can. This recipe is based on the familiar roast beef and cheddar profile listed on the Arby's menu, then adjusted for a home oven and a family-size baking dish.
Make It A Meal
This casserole is rich, so I like it with something sharp or crunchy. Dill pickles, a chopped iceberg salad, roasted broccoli, or a bowl of vinegar slaw all work. If you want a full fast-food-style dinner, serve it with fries and extra red sauce on the side. For a similar beef-and-cheese dinner with a crispy potato angle, see the French Fry Casserole with Ground Beef and Cheddar.
Leftovers And Reheating
Leftovers keep well for 3 days in the refrigerator. Cover the dish with foil and reheat at 325°F until hot in the center. A microwave works for single portions, but the bread will soften more. The USDA recommends reheating leftovers to 165°F, and their leftovers safety guide is a useful reference if you are cooking ahead.
Easy Family Variations
For extra cheese, scatter a handful of shredded cheddar over the top during the last 10 minutes of baking. For more onion-roll flavor, add dried minced onion to the bun cubes before toasting. You can also tuck in a thin layer of cooked onions if your family likes them. If sandwich casseroles are your thing, the Copycat Chick-fil-A Honey Pepper Pimento Chicken Sandwich Casserole hits the same fun dinner idea with chicken instead of beef.
Summary
Serve this bake hot from the oven with pickles, a crisp salad, or simple fries. It is rich, saucy, and built for a hungry table.
FAQs
- Can I use deli roast beef for this casserole?
Yes. Thin-sliced deli roast beef is the easiest choice because it stays tender and already has the right sandwich feel. Chop it into wide strips so it layers well and does not clump in the baking dish.
- What can I use instead of onion buns?
Brioche buns, hamburger buns, or soft hoagie rolls all work. If you skip onion buns, add a teaspoon of dried minced onion or a little onion powder to the toasted bread cubes.
- Can I make it ahead?
You can make the sauces and toast the bun cubes a day ahead. Assemble the casserole right before baking so the bread keeps some texture instead of soaking too long.
- How do I keep the cheese sauce smooth?
Use medium-low heat and add the cheese after the milk mixture has thickened. Pull the pan off the heat before stirring in the cheese so it melts gently instead of turning grainy.
- How should I store leftovers?
Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat covered in a 325°F oven or in short microwave bursts until hot.
- Can I make this spicier?
Add cayenne to the red ranch sauce or stir a spoonful of prepared horseradish into the cheese sauce. Start small because the casserole concentrates as it bakes.
