A delicious beef rosto sandwich, with toasted grainy bread, Dijon mustard, roast beef, fried egg, beer cheese and topped with lettuce and tomato. It would be a great addition to your weekend menu!

roast beef sandwich with cheddar beer sauce

This rosto sandwich is a roast beef sandwich elevated! In addition to the roast beef, there is a spread of Dijon mustard, beer cheese and a fried egg, all finished with lettuce and tomato.

Ingredients and Substitutions

Roast Beef – I roasted up a small beef roast for this rosto sandwich, but it is also the perfect use for leftover roast beef. Thick slices of deli roast beef. Left-over beef pot roast would also work here.

Bread – I’ve used a multigrain bread here, but I’ve also made it with sourdough bread and it was great, as well. Any bread you have or enjoy is just fine here.

Beer – I’ve used an Ale here, but use any beer you have or enjoy.

Cook’s Notes

For the roast, I used a small sirloin roast and roasted it off in the oven. I love to use my cast-iron skillet for roasts and it also allows this recipe to go from oven to stove-top easily. Simply remove the roast to a cutting board to rest while using the same skillet to quickly make the cheddar ale sauce. It also means you get the browned bits as part of the sauce!

Be sure to cook your roast only to about medium rare. That means taking it out of the oven when it hits 125° F. You can also roast the beef ahead, cool slightly then refrigerate whole. Then slice for the sandwiches later.

Finally, if you are in to the idea of this sandwich, but not necessarily the roasting the beef yourself part, you can always use a nice deli roast beef instead. Just ask to have it thickly sliced.

Roast Beef Sandwich with Cheddar Ale Sauce

Make this on the BBQ! Simply roast the beef in a cast-iron skillet on your BBQ, then you can make the sauce in the same skillet on the BBQ, too!

Want to save this recipe?

Enter your email & I'll send it to your inbox. Plus, get great new recipes from me every week!

Save Article

By submitting this form, you consent to receive emails from Seasons and Suppers.

roast beef sandwich with cheddar beer sauce

Get the Recipe: Beef Rosto Sandwich with Beer Cheese

A delicious rosto sandwich with homemade beer cheese. You can roast the beef yourself or use deli-sliced roast beef.
5 stars from 2 ratings
Prep Time: 15 minutes
Cook Time: 50 minutes
Total Time: 1 hour 5 minutes
Yield: 6 servings


Roast Beef:

  • 2 lb. Sirloin roast
  • Freshly ground pepper

Cheddar Ale Sauce:

  • 1/4 cup butter
  • 1/4 cup all-purpose flour
  • 1/2 cup British Ale, or beer of your choice
  • 1/2 cup beef broth, or omit and use a full 1 cup of beer, if you like it beer-y
  • 1 1/2 cup aged cheddar
  • Dash Worcestershire sauce
  • Salt and pepper, to taste

For the sandwich:

  • Thick sliced grainy bread, toasted and buttered
  • Dijon mustard
  • Thinly sliced roast beef
  • Fried Egg, Optional
  • Cheddar Ale Sauce
  • Leaf lettuce
  • Thin tomato slices
  • Salt and pepper, to taste


  • For the roast: Preheat oven to 450° F. Place a layer of freshly ground pepper on to a flat surface or plate. Dry roast, then roll the top in the pepper. Place in to cast-iron skillet or shallow roasting pan. Place in preheated oven and immediately reduce heat to 325° F. Roast to medium-rare (125° F. when tested with a thermometer), about 35-40 minutes.
  • Remove roast to a cutting board and loosely tent with aluminum foil. Meanwhile, place skillet or pan used to roast beef on the stove-top over medium heat.
  • For the Cheddar Ale Sauce: Melt butter, then add flour. Cook flour, stirring constantly and scraping up the browned bits on the bottom of the pan for about 1 minute. Add beer, stir and allow to simmer for 1 minute. Add beef broth, cheddar, Worcestershire and salt and pepper to taste. Cook, stirring, until sauce thickens.
  • (If including a fried egg, heat a small skillet to medium and fry egg until cooked but still runny.)
  • To assemble sandwich: Toast bread, butter and spread a layer of Dijon mustard on it. Thinly slice beef and place on top. Top the beef with a fried egg, if using. Spoon warm cheddar ale sauce over-top, then top with lettuce and tomato. You can serve this open-faced, with a knife and fork or with a top piece of bread, as a sandwich.


Be sure to read the "Cook's Notes" in the original post, for more tips, options, substitutions and variations for this recipe!
Cuisine: American
Course: Main Course
Serving: 1serving, Calories: 503kcal, Carbohydrates: 5g, Protein: 50g, Fat: 29g, Saturated Fat: 18g, Cholesterol: 176mg, Sodium: 585mg, Potassium: 672mg, Vitamin A: 830IU, Calcium: 436mg, Iron: 1.9mg
Tried this recipe?Mention @seasonsandsuppers on Instagram or tag #seasonsandsuppers.