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Leftover Corned Beef Au Gratin Potatoes Recipe

One of my favorite things about every single holiday is the leftovers. You could not pick a better meat to use in cheesy potatoes than leftover corned beef. This Corned Beef Au Gratin Recipe is a great way to use up all the meat and stretch your dollar while also enjoying every last bite!

A spoonful of this Corned Beef Au Gratin Recipe lifted out of the pan for a close-up shot. Hostess At Heart
Cheesy Corned Beef Au Gratin Potatoes

Some things are just hard to make in small amounts, and corned beef is definitely in that category. We always bake a large corned beef for St. Patrick’s Day so that we have leftovers. And leftovers can be made into delicious second or third meals, which saves time and money. Make our Corned Beef Potatoes Au Gratin and you’ll be putting that extra meat to good use.

Why You’ll Love Corned Beef Potatoes Au Gratin

  • Easy to make and quick! Cheesy homemade Au Gratin Potatoes loaded with rich salty leftover Corned Beef is a perfectly balanced one-dish meal ready in less than 30 minutes. If you have extra time, add a salad for greens and fresh home-baked bread and you are golden!
  • Uses leftovers. If there is one thing I cannot stand, it’s letting good leftovers go to waste. That’s why finding dishes to make for dinner that use leftover meat is genius. Plus, it saves you time because the meat is already cooked.
  • Tastes amazing. Cheesy potatoes are the bomb. Cheesy Corned Beef and Potatoes is next level. Yum. It’s versatile. You can serve Potato Au Gratin as a delicious dinner or as a great side dish the whole family will love.

What’s the difference between Au Gratin and Scalloped Potatoes?

Au gratin potatoes have cheese baked on top to get that crispy, melty deliciousness. Scalloped potatoes are just sliced potatoes baked in a creamy sauce – no cheese. So au gratin is cheesy, scalloped is creamy. Same idea of sliced potatoes baked in an amazing sauce, but au gratin takes it up a notch with that cheesy sauce often called a bechamel. Now I’m hungry!

Ingredients you’ll need for this recipe

Ingredients for Corned Beef Potatoes Au Gratin: Potatoes, gouda cheese, corned beef cubes, cheddar cheese, flour, heavy whipping cream, butter, salt and pepper.
Au Gratin Potatoes with Corned Beef Ingredients
  • Potatoes. We’ll give you some great potato options.
  • Cheddar Cheese. Cheddar melts beautifully and adds such a delicious flavor.
  • Gouda Cheese. Smoked gouda is especially nice!
  • Heavy Cream. You can use either heavy cream or heavy whipping cream, which vary only slightly in fat content and are interchangeable. Some grocery stores only carry one or the other.
  • Corned Beef Brisket. This should be already cooked.
  • Butter. Unsalted butter is a good idea for this dish.
  • Flour. To thicken the sauce.
  • Salt and Pepper. To taste. You might need to go easy on the salt because of the corned beef.

How To Make Corned Beef Potatoes Au Gratin

Please note, that the printable recipe card has ingredient quantities, complete instructions, and nutritional information. The following is a quick overview of the recipe.

Step One. Get ready to make your Corned Beef Au Gratin Recipe.

Preheat the oven and spray your baking dish. Set the pan aside.

Step Two. Cook the potatoes in cream.

In a large Dutch oven, melt the butter and whisk in the flour to make a rue. Now add 1/4 cup of the cream and whisk until thickened. Add the remaining cream.

A Dutch oven with a combination of flour and melted butter to make a rue. Hostess At Heart
Combine flour and melted butter for the rue.

Add the sliced potatoes and cook for fifteen minutes over a medium-high heat. They will be finished in the oven. This speeds the process up.

Sliced red potatoes added to cream in a Dutch oven. Hostess At Heart

Step Three. Add the remaining ingredients except the reserved cheddar for the top.

Add the gouda cheese, half of the cheddar cheese, and the diced corned beef. Stir to combine.

A casserole dish filled with sliced potatoes and diced corned beef in a thick cheesy sauce. Hostess At Heart
Add ingredients to a casserole dish

Step Four. Bake your Corned Beef Potatoes Au Gratin.

Pour all of the ingredients into the casserole dish. Top with remaining cheddar cheese. Bake.

Unbaked Corned Beef Potatoes Au Gratin. This is what it looks like in the pan before it is baked.

Frequently Asked Questions

What kind of potatoes should you use for au grautin?

A good starchy potato is best. Red potatoes russets and Yukon gold potatoes are great options. They will not become too soft while baking.

How To Reheat & Store this Corned Beef Au Gratin Recipe

Best way to store corned beef with potato

This dish should be refrigerated in an airtight container and used within a few days. When storing food, you have to remember the age of the ingredients. If you baked your corned beef 2 days ago, and it’s ok to store for 5 days, you only have 3 days in which to consume your new dish.

There’s nothing wrong with dicing up the corned beef putting it in serving-sized containers and freezing it. That will give you more options for using it.

Can I freeze au gratin?

Yes, you can freeze potato gratin. You can, however, the texture of the creamy sauce and cheese will change and could make the dish unpalatable.

How to reheat au gratin corned beef?

The easiest way to reheat this dish is in the microwave until it is hot and bubbly. A single serving should only take two or three minutes.

Top down view of a casserole dish filled with Corned Beef and Potatoes topped with melted cheese. Hostess At Heart


  • Top with toasted bread crumbs or potato chips.
  • Add veggies! Green peppers and a white onion are an ideal way to add flavor.
  • This recipe works great with ham, ground beef, or sausage, instead of corned beef for a whole new hearty meal.
  • We love cheddar but other semi-soft cheeses such as Colby, Swiss cheese, or Grueyere would be delicious.

Hostess Tips for Corned Beef Potatoes Au Gratin

  • Use a mandolin slicer! You will have perfect potato slices in a fraction of the time. If you don’t have one, put it on your wish list. Slicing your potatoes the same thickness will guarantee that they bake evenly and your dish is finished baking as soon as possible. If you don’t have a mandoline slicer or mad knife skills, be sure to check the potatoes in several areas of the dish for doneness.
  • You do not have to peel the potatoes. Scrub them well and leave them on for a more rustic take.
  • You can prepare this dish a day ahead of time! Get it all ready and place it in the fridge, covered. About an hour before you want to bake the corned beef and potatoes, pull it from the fridge to warm up gently so that your pan does not break in the oven. Even if you are using a metal pan, letting it warm up a bit before putting it in a hot oven is a good idea.
A single serving of Leftover Corned Beef and Potatoes on a plate. Hostess At Heart

Still looking for leftover recipes? Check these out!

Take a look at all of our delicious Corned Beef Recipes.

I hope you enjoyed this delicious recipe as much as we do. Drop me a comment below, and don’t forget to give it a star rating. ⭐⭐⭐⭐⭐. Your comments and ratings help others decide if this recipe is for them too.

A spoon lifting a serving of cheesy Au Gratin Potatoes and Corned Beef from a casserole dish. Hostess At Heart

Corned Beef Au Gratin Potato Recipe

Author: Hostess At Heart
Turn leftover corned beef into a delicious and easy Corned Beef Au Gratin Recipe. Perfect way to stretch your dollar and enjoy every last bite.
5 from 2 votes
Prep Time 20 minutes
Cook Time 25 minutes
Total Time 45 minutes
Course Main Dish, Side Dish
Cuisine American
Keyword: Au Gratin, Cheese potatoes, Potato Casserole, St. Patricks Day
Servings: 8


  • 3 lbs potatoes sliced 1/4 inch thick
  • 1 cup cheddar Cheese – shredded
  • 1 cup gouda Cheese – shredded
  • 1 quart heavy cream
  • cups corned beef brisket or 2 cups, cooked and diced
  • 1 tbsp butter
  • 2 tbsp flour
  • Salt and pepper to taste


  • Preheat the oven to 350 °F. Spray a 9×13 baking dish with non-stick cooking spray. Set aside.
  • In a large dutch oven, melt the butter and stir in the flour and cook for 1 minute. Add 1/4 cup of cream and cook, stirring continuously until thick. Add the remaining cream.
  • Add the sliced potatoes to the cream and bring to a boil on high. Turn the heat down to medium-high and cook for 15 minutes, stirring occasionally. If the sides or bottom of the pan start turning brown, turn the heat down to medium.
    Note: the potatoes will not be completely cooked. They'll finish in the oven.
  • Add the gouda cheese, half of the cheddar cheese, and the diced corned beef. Stir to combine.
  • Pour all of the ingredients into the baking dish. Top with remaining cheddar cheese. Bake for 25 minutes uncovered or until the potatoes are cooked.


This recipe can be made ahead of time and baked right before serving. Remove it from the refrigerator and let come to room temperature, for approximately 1 hour.


Serving: 8gCalories: 618kcalCarbohydrates: 6gProtein: 17gFat: 59gSaturated Fat: 35gPolyunsaturated Fat: 2gMonounsaturated Fat: 16gTrans Fat: 0.1gCholesterol: 192mgSodium: 792mgPotassium: 275mgFiber: 0.1gSugar: 4gVitamin A: 2004IUVitamin C: 13mgCalcium: 281mgIron: 1mg

Nutritional Disclaimer

This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.

Tried this recipe?Let me know how it was!

If you enjoyed this recipe check these out!

We love cooking with potatoes! So much goodness, and such a warm, comforting way to fill up hungry bellies. When you don’t know what to do with your potatoes, try making Roasted Garlic Fingerling Potatoes Recipe or these Twice baked potatoes. If you want to make something a bit more unusual and fancy, try Garlic-Basil Red Hasselback Potatoes. For one last fun option: Potato Rolls.

Did you enjoy this recipe? Don’t forget to pin it for later and follow me on Pinterest for more delicious recipes like this one!

Top down closeup view of a spoon holding creamy protatoes au gratin with diced corned beef and topped with melted cheese - Hostess At Heart
5 from 2 votes (2 ratings without comment)
Recipe Rating


Tuesday 9th of January 2024

The gouda cheese takes this recipe over the top! I made using some leftover brisket, but I am saving this to make with our leftover corned beef after St. Patty's day!

Julie Menghini

Friday 12th of January 2024

It really does and so glad you enjoyed it. Thank you.


Tuesday 9th of January 2024

Brooks is a big fan of corned beef and when I whipped this up he was surprised, one that I made it, and two that he got to enjoy it all himself. He doesn't like to share so I made a second one for me!

Julie Menghini

Friday 12th of January 2024

That's definitely a win win! Thank you!

Laura Ashley Johnson

Wednesday 3rd of January 2024

Definitely a new favorite! My family has already requested it again!

Julie Menghini

Friday 5th of January 2024

Thank you, Laura!


Monday 1st of January 2024

This is such a great way to use up leftover corned beef. BRILLIANT. I think this tasted better than the corned beef! So tasty!

Julie Menghini

Wednesday 3rd of January 2024

Thank you, Janelle! We love corned beef but the leftovers are our favorite I believe.


Monday 1st of January 2024

This was totally the comfort food our NYE gathering needed. It was so cozy and delicious!

Julie Menghini

Wednesday 3rd of January 2024

I'm so glad that you enjoyed it!

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