Hot Roast Beef Sandwiches with Cheddar Cheese Sauce

These hot roast beef sandwiches with cheddar cheese sauce are so easy to make – the cheese sauce takes only a couple of minutes and is so creamy and smooth.

A stack of three hot roast beef sandwiches with cheddar cheese sauce

Hot Roast Beef Sandwiches

About four years ago I shared a recipe for hot roast beef sandwiches and I feel like I should mention them because it’s likely they’ll show up in the “recommended” page thing at the end of the post and you might wonder why I’m sharing something so similar. But here’s the deal – these new-fangled hot roast beef sandwiches are totally different and the main difference is the cheese sauce. The old recipe has an old-fashioned cheese sauce made from a bechamel sauce, but the cheese sauce I’m sharing today, well, it’s a less-than-five-minutes microwave sauce. No flour, butter, or whisking required.

And I thought about replacing the old recipe with the new, but I still like the old way of making cheese sauce so I figured there’s enough room in this blog for two kinds of hot roast beef sandwiches. Did I mention they’re topped with a creamy smooth cheddar cheese sauce?

a hamburger bun with hot roast beef topped with creamy cheddar cheese sauce

Microwave Cheddar Cheese Sauce

So let’s talk about that cheese sauce. First, it’s so simple to make you’ll want to start adding a warm and oozy cheese sauce on all your sandwiches. I got the idea from Bon Appetit and their amazing 3-ingredient cheese sauce and rescaled it to work for these sandwiches. It’s the sort of sauce that stays smooth and creamy even after it cools and turns these hot roast beef sandwiches into something sort of like what you might get at a famous fast food restaurant. You know, the one with the horsey sauce? Well, now you can stay home and make an even better version of that drive-through favorite. Pop some curly fries in the oven and you’re all set.

Some Ingredients You’ll Need

  • Deli roast beef sliced thin. It really is so much better than what you get in a package, so treat yourself and get some of the good stuff at the deli counter.
  • Mayo and creamy horseradish
  • Mild cheddar cheese, but feel free to get creative. Any good melting cheese should work well.
  • The secret to the cheese sauce is evaporated milk. Look for it in the baking aisle.
  • The cheese is tossed with some cornstarch which thickens the sauce and keeps the cheese smooth instead of stringy.
Hot roast beef on a sesame hamburger bun with cheddar cheese sauce

More Hot Sandwiches


Hot Roast Beef Sandwiches with Cheddar Cheese Sauce

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4.6 from 8 reviews

These hot roast beef sandwiches are quick and easy thanks to a simple cheddar cheese sauce (from Bon Appetit) that’s made in the microwave.

  • Author: April Anderson
  • Prep Time: 10 minutes
  • Cook Time: 5 minutes
  • Total Time: 15 minutes
  • Yield: 4 sandwiches 1x
  • Category: Dinner
  • Method: Saute
  • Cuisine: American


  • 1 1/2 tsp creamy horseradish
  • 1/4 cup mayonnaise
  • 1 cup shredded mild cheddar cheese (see note)
  • 2 tsp cornstarch
  • 1/2 cup evaporated milk
  • 1 tbsp butter
  • 1/2 pound thin-sliced roast beef
  • 4 hamburger buns


  1. Combine the horseradish and mayonnaise in a small bowl.
  2. Place the shredded cheese in another small bowl and toss it with the cornstarch. Add the evaporated milk and heat it in the microwave for about minute or so until smooth.
  3. Melt the butter in a skillet and add the roast beef. Cook it for a few minutes until it’s warmed through. If needed heat it again for 30 seconds before you build the sandwiches. Divide the horseradish mayonnaise among the buns (I like it on the bottom bun). Top with the roast beef and cheese sauce. Serve warm.


For the best results, shred block cheddar cheese for this recipe instead of using pre-shredded cheese, which has stabilizers that can cause issues with the sauce.


  • Serving Size: 1 sandwich
  • Calories: 463
  • Sugar: 6.4g
  • Sodium: 755.4mg
  • Fat: 27.5g
  • Saturated Fat: 10.2g
  • Unsaturated Fat: 15.5g
  • Trans Fat: 0.3g
  • Carbohydrates: 34g
  • Fiber: 1.7g
  • Protein: 13.9g
  • Cholesterol: 57mg

Do you love this recipe? Don’t forget to leave a comment and your recipe star rating!


  1. Arby’s is one of my favorite fast food restaurants but they’re so expensive that I almost never go there. These sandwiches were so delicious that I’m already planning on making them again this week. Thanks for the recipe!

    1. Also wondering if there is a substitute for the evaporated milk? Just trying to make this with stuff I already have! Thanks again!

      1. I’ve only tried it with cornstarch and evaporated milk – I’m not sure what the consistency will be like with the substitutions, but I suspect it won’t be as creamy and the cheese might be stringy. Let me know if you try it!

  2. This is a great recipe for leftover roast beef. I sliced it quite thin and it warmed nicely in the butter/saucepan. Instead of buns, I made some fresh sliced sourdough bread that I buttered lightly and grilled. Once the bread was grilled I spread both slices with the mayo mixture, topped it with the meat and cheese. Scrumptious! I will definitely use this recipe again.

  3. These were super delicious! I heated my cheese mixture for 3 minutes, stirring a couple times. I used a glass bowl so it took longer! Very yummy recipe, we loved the horseradish mayo!

  4. Delicious! I was thinking how much i would like a beef and cheddar from Arby’s and your recipe was even better! Do you think the cheese sauce will reheat well? I have leftovers.

    1. I think the sauce should rewarm ok – you may need to add a little more milk to thin it.

  5. This was good. We did decide that it’s better without the horseradish. Probably just a personal preference.

    I loved how quick and easy it was. Especially making the cheese sauce in the microwave. Thanks for the quick dinner.

  6. I attempted to make the cheese sauce 3 times and it became a thick glob every time. I reduced the corn starch on the 2 nd attempt: same result. I used no corn starch on the 3rd attempt: same result. I used shredded mild cheddar cheese. Any thoughts?

        1. No, you didn’t miss anything – I’ve made it with pre shredded cheese before without problems, but I wonder if different brands work differently. I am updating the recipe with this info – again, I’m sorry you had issues!

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