Duchess Potatoes Casserole (Leftover Mashed Potatoes)

Duchess Potatoes Casserole From Leftover Mashed Potatoes

If you follow me, you might know I’m all about leftovers and transforming them into marvelous new dishes, so I wasn’t daunted at all by the five pounds of mashed potatoes I had when I made my Slow Cooker or Oven Make Ahead Mashed Potatoes. I had a few ideas, but after seeing Gail’s post for her Duchess Mashed Potatoes on her site, Snap Shots in Cursive, I couldn’t get them out of my mind. Out the window flew any thoughts of gnocchi and pierogies, and inspired, I decided to make this Duchess Potatoes Casserole From Leftover Mashed Potatoes.

Duchess Potatoes Casserole (From Leftover Mashed Potatoes)

Duchess Potatoes Casserole (From Leftover Mashed Potatoes)


Duchess Potatoes like Gail’s (click over they’re gorgeous!) are the epitome of good taste and smack of dinner parties, and Duchess Potatoes simply transform a mashed potato into a thing of beauty. There’s usually a little cream involved, a few egg yolks and oh, please don’t forget the cheese! This post, though, is about transforming leftovers, so see Gail’s post for the real deal.

About Duchess Potatoes Casserole From Leftover Mashed Potatoes:

It’s actually a little hard to believe how different Duchess Potatoes are from your mashed potatoes, just by adding those few simple ingredients. They’re lighter and airy and you can never discount how much a little golden brown deliciousness adds to any food. Raise your hand if you live for those browned crispy edges! I’d raise mine but I’m typing, lol

And while every mashed potato might not be a good contender to pipe out for the traditional Duchess Potatoes (maybe, especially, if they’re too creamy) this Duchess Potatoes Casserole (From Leftover Mashed Potatoes) is just the perfect thing for just about any mash. But first, I had to find out if there was a “formula” a kind of ratio to use between the potatoes, egg yolks, and cheese that was going to be a perfect texture for a casserole.

Duchess Potatoes Casserole (From Leftover Mashed Potatoes)

Duchess Potatoes Casserole (From Leftover Mashed Potatoes)

Making Duchess Potatoes Casserole From Leftover Mashed Potatoes:

I looked at a few recipes (starting with Gail’s, of course, and thank you, Gail, for the inspiration!) and I think I cracked a code. It seems like about an egg yolk for each one and a half cups of mashed potato, an ounce of cheese (if your potatoes don’t already have cheese; I thought my potatoes had plenty with all the cream cheese) and a little milk or cream if you have it is even better (if needed, just enough to make them creamy enough to stir but not enough to make them “wet”) will do the trick.

There’s really a bit of a judgment call in any of the milk or cream you might add to your mashed potatoes because everyone’s mashed are a little different. Some are only made with milk and butter, other’s like my Slow Cooker or Oven Make Ahead Mashed Potatoes might have sour cream and creamed cheese. And still, others, like Gail’s Havarti Mashed Potatoes might already have cheese in them. Heck, this recipe will even work with “loaded” mashed potatoes complete with sour cream, cheese, and bacon.

The bottom line, though, it really doesn’t matter because your Duchess Potatoes Casserole (From Leftover Mashed Potatoes) are going to be delicious no matter what. It’s kind of like making Traditional Irish Potato Cakes, another great use for leftover potatoes. You’ve got to allow for a little “personality” shining through from your original mashed potatoes and accepting of the outcome.

Saving Money on Duchess Potatoes Casserole From Leftover Mashed Potatoes:

Has anyone noticed potatoes are getting pricier at the store? I’ve noticed that so many are now “name brand” and in smaller bags. And they do look prettier, all washed and uniform in size but you pay extra for that. Look to see if you can’t find larger, 10-pound bags of potatoes and pick them up. You can give them a sort yourself and use the larger, more uniform ones for bakers and the odd-sized shaped ones for recipes like this where size doesn’t matter. Potatoes that aren’t well-washed store better anyway, and you’ll want to store them in a dark place, a paper bag works well, away from onions.

So watch for sales, especially during pre-Holiday and Holiday weeks, like Thanksgiving and Christmas for great prices on butter and cream. Check Aldi and Costco, too. Their everyday prices are sometimes better than the grocery store sales prices. Cream keeps for weeks past it’s “buy by” date and butter freezes beautifully.

Shop well for that cheese. Watch the grocery store specials and coupon deals; grocery store cheeses keep for weeks, unopened and can be frozen. Buy it when it’s cheap and use it as needed. Grocery store cheese has become very competitive with so many newer brands along with the store brands. You’ll likely find specials all through the holiday season.

Be sure to check my post on what to watch for on sale over Thanksgiving, Christmas and New Year’s holiday sales and stock up at a low on many items. And don’t forget about your two extra egg whites. I have a ton of ideas and instructions on how to freeze on my post Over 75 Ways to Use Leftover Egg Whites.

Duchess Potatoes Casserole (Leftover Mashed Potatoes)

Duchess Potatoes Casserole (Leftover Mashed Potatoes)

Duchess Potatoes Casserole (From Leftover Mashed Potatoes)

  • Servings: 4 to 6
  • Difficulty: easy
  • Print

Scale recipe up or down as needed. Just watch the timing if using a small casserole.

  • 3 cups leftover mashed potatoes
  • 2 egg yolks
  • 2 ounces cheese, grated (may be omitted if potatoes already contain cheese) 2 ounces is about 1/2 cup grated cheese
  • enough cream or milk to thin potatoes (see text)
  • if desired, one or two scrapings from a nutmeg or the faintest pinch of powdered nutmeg, or a little garlic powder may be added.

Preheat oven to 350 degrees F.

Mix together mashed potatoes and egg yolk. Add enough cream or milk to thin a bit if needed; mixture should be able to be stirred. Add in a little nutmeg or garlic powder if desired. Scrape into well-buttered casserole. Place a few designs on top with the back of a spoon, swirling or shingling as desired..

Bake for about 30 to 35 minutes until golden browned and slightly puffed. (They will deflate a bit upon cooling.)

Note: if mashed potatoes are very lean to start with, brush the top of the mashed potatoes after you’ve added the “design” with a little melted butter, about 2 teaspoons or so.


I’ll be sharing Duchess Potatoes Casserole (From Leftover Mashed Potatoes) at Fiesta Friday #251 where this week I’m one of the co-hosts along with Monika @ Everyday Healthy Recipes.

When the gravy's gone don't be sad about your leftover mashed - transform them into Duchess Potatoes Casserole (From Leftover Mashed Potatoes) Super easy & so Delish! #LeftoverMashedPotatoes #DuchessPotatoCasserole

31 thoughts on “Duchess Potatoes Casserole From Leftover Mashed Potatoes

  1. Melissa

    Another yummy recipe! I made a ton of this with nine pounds of mashed potatoes leftover from thanksgiving! I added freshly grated parm to kick this up a notch and not a crumb was leftover. Thank you for your detailed notes on every post And recipes . I look forward to trying many more of your recipes!

    • FrugalHausfrau

      Oh gosh, was that a typo? Nine pounds!! Wow! I love the idea of the Parmesan! And thanks again for taking the time to comment…


  2. My mother used to make these all the time. She added cottage cheese and an egg, they were delicious. I also like them on top of a shepherd’s or cottage pie. I could make a meal of them. Have you ever read MFK Fisher? One of her secret private meals was mashed potatoes with ketchup.

    • FrugalHausfrau

      Hi Liz, I have made two different shepherd’s pie on my blog and never thought to do that! It would make the potatoes have such a beautiful texture and golden color! 🙂

  3. Joyce Corcoran

    I love fried mashed potatoe patties which is probably not the healthiest but my grandma would make them for me on special occasions. She would take left over potatoes and flour and salt and pepper the patty. She would cook some bacon, drain off most of the grease, add some butter and fry potato patty. She would then make an egg in same pan and serve egg, bacon and potato patty on a plate. Didn’t have it often but so very good. I’m 70 now and still make this for me when I have left over mashed potatoes.

    • FrugalHausfrau

      It sounds a lot like the Irish Potato Cakes my Mom made, only better because of bacon! I bet you’re Irish, too, at least guessing from the name Joyce?

      It doesn’t sound like it’s done too much harm if you’re 70 and still cooking. 🙂 And on the internet! But like you said not, too often and moderation, right! Thanks for commenting, Joyce!


  4. Ron

    Mashed potato leftover casseroles are what I’m all about and your Duchess potatoes are looking mighty not leftover to me. But, potato pierogies fried in butter, now that’s some serious yum.

    • FrugalHausfrau

      I’m kinda craving them, now. Now they’re a pain to make…but just so darned good! I’m determined to eat a bit better in the next couple weeks, so no pierogies…I have to balance things out with the X-mas goodies coming up!! 🙂

  5. Pingback: Duchess Potatoes Casserole (From Leftover Mashed Potatoes) — Frugal Hausfrau | My Meals are on Wheels

  6. Hey Mollie– love the specifics on your ingredients–makes it really clear. And these potatoes really look delicious! Certainly elevates mashed potatoes!! You are so smart! Love using leftovers too. Hope you had a lovely Thanksgiving. How did it turn out??

  7. I freeze my leftover mashed potatoes so rarely have any issues but this is an interesting new way to serve them.

    PS: I also have a baked potato puff (with choux paste) recipe that I want to try in the future … a twist on the regular fried Dauphine potatoes.


    Only one problem with trying either of these recipes is the fact that I have NO potatoes in the house. I woke up to rain so I’m sticking with pasta and rice as sides today in my cooking. 🙂

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