Keto Roast Beef Onion Bun Chaffle with Arby’s Horsey Sauce

Do you ever crave an Arby’s Roast Beef sandwich?  My favorite was the Onion Bun with the yummy creamy horseradish mayo.  Well this is a pretty darn good copycat of that experience! Roast Beef Chaffle Sandwich with Keto Onion Bun chaffle and that famous Horsey sauce! Yummy!

Keto Roast Beef Onion Bun Chaffle with Arby’s Horsey Sauce

Being on low carb and Keto for so long, sometimes I just forget what it’s like to have a sandwich!

I used to especially like Arby’s Roast Beef sandwiches!  I know that some people like the red sauce they make but I was always a huge fan of the Horsey sauce.

A creamy sauce with horseradish for bite.  And it pairs perfectly with cold leftover roast beef.  I even love it with hot chicken wings.  So make lots of it and save it for other things!

Roast beef and salad with horseradish sauce is one of my favorite simple meals!

Sliced roast beef with horseradish sauce and greens on a plate

Things you will need for this Keto Arby’s copycat recipe

Roast Beef Chaffle Tips and Tricks

  • You are going to be making 2 Chaffles for this Arby’s sandwich
  • If you want to make these for a family, you can easily double or quadruple the Chaffle part of the recipe and just make all the Chaffles before putting the sandwiches together. 
  • The copycat Horsey sauce yields about 10 tbsp of sauce which is more than enough for several sandwiches or save it for other meals
  • Prepare the copycat Horsey the day before for best flavor.
Onion Chaffle with roast beef and sauce on a white plate

Keto Roast Beef Onion Bun Chaffle with Arby's Horsey Sauce

Yield: 1
Prep Time: 5 minutes
Cook Time: 5 minutes
Total Time: 10 minutes

This Keto onion bun chaffle with roast beef and creamy horseradish sauce will have you dreaming of Arby's, without all the carbs!


Horseradish Sauce

  • 1/2 cup mayonnaise
  • 2 tsp keto sweetener
  • 2 tbsp horseradish from a jar
  • salt to taste

Onion Bun Chaffle

  • 1 egg
  • 1/2 cup grated mozzarella cheese
  • 1 tbsp minced onion
  • salt to taste
  • 4 ounces deli roast beef or cold leftover roast beef


  1. Make the Horseradish Sauce ahead of time so the flavors can develop
  2. Combine the mayonnaise, sweetener, horseradish and salt in a bowl and set aside in the fridge until ready to make the Chaffles
  3. Plug in the mini waffle maker to preheat
  4. In a small bowl, beat the egg, grated cheese, minced onion and salt together.
  5. Once the waffle maker has heated up, pour half the batter (about 1/4 cup) onto the maker and close the lid for 4 minutes.
  6. Remove the Chaffle and allow to cool on a rack
  7. Repeat with remaining batter.
  8. Assemble the sandwich by placing the roast beef on one chaffle, top with 1-2 tbsp of Horsey Sauce and top that with the other onion bun chaffle.


Make the Horsey Sauce the day before to have the best flavor and save time!

Nutrition Information:
Yield: 1 Serving Size: 1 Sandwich
Amount Per Serving: Calories: 593Total Fat: 40gCarbohydrates: 2gNet Carbohydrates: 2gFiber: 0gProtein: 55g

Did you make this recipe?

Please leave a comment on the blog or tag me on Instagram! @ketogenic.woman. Follow me on Pinterest by clicking the Pinterest button to the left!

More Keto and Low Carb Chaffle and Waffle Recipes!

Get out your waffle maker! Chaffle is the new Waffle, and both are perennial family favorites! And they are not just for breakfast anymore!

Save this Keto Onion Bun Chaffle Recipe to Pinterest!

Pinterest Pin showing Onion Bun Chaffle

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