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Creamy, fluffy, and full of flavor, this Mashed Potato Casserole is the perfect way to prepare mashed potatoes for a gathering or the holidays. It's rich, buttery, and just indulgent enough to feel special.
If your mashed potatoes always seem to cool off before the turkey hits the table, this mashed potato casserole is your stress-free fix. It delivers the same comforting flavor you love, but in a make-ahead version that lets you actually enjoy your meal.
Kristen's Keys for Mashed Potato Casserole
For a mashed potato casserole that has everyone going back for seconds (and maybe even thirds), pay attention to a few key pointers.
- Prepare in advance. While you can bake this casserole right after assembling it, part of its charm is how well it works as a make-ahead holiday dish. Assemble and refrigerate it up to 2 days in advance, or freeze it for up to 1 month prior to baking. It's such an easy way to get a head start on your holiday meal.
- Use starchy potatoes. Yukon golds or russets are your best bet-they mash up smooth and absorb butter like a dream. Waxy potatoes (like red potatoes) can turn gummy.
- Use full-fat dairy. Sour cream, butter, and cream cheese give that classic rich texture. Lower fat versions just don't hold up the same way.
5-Star Reader Review
This was very easy to make and a big crowd pleaser! I especially liked being able to make it the evening before. Has been added to our favorites list! -Lana ⭐⭐⭐⭐⭐
How to Make Mashed Potato Casserole
While easy to make, this step-by-step section is provided to help you feel confident whether you are a seasoned cook or a beginner.
Step One: Cook Potatoes
Peel and cut your potatoes into even chunks, then place them in a large pot of cold, salted water. Bring to a gentle boil and cook until fork-tender, about 15-20 minutes.
👉🏻Start in cold water and heavily salt. This helps the potatoes cook evenly and be flavored from the inside out.
Step Two: Drain Potatoes
Once the potatoes are fork-tender, drain them in a large colander but don't stop there. Return the potatoes to the hot pan and simmer until all the moisture has evaporated-about 1-2 minutes.
👉🏻Don't skip this step! This This keeps your casserole fluffy, not watery.
Step Three: Mash Potatoes
Mash the potatoes using a potato masher or ricer until smooth and fluffy. Avoid using a handheld mixer for this step, which can make your potatoes gluey.
Step Four: Flavor the Potatoes
To make this casserole creamy and flavorful, mix in softened cream cheese, sour cream, melted butter, milk, minced onion (if using), salt, and pepper until creamy and combined. Add the eggs, and mix again (adding the eggs last allows the potatoes to cool slightly so the heat doesn't scramble the eggs).
👉🏻Why a Mixer Now? After mashing the potatoes, you can mix in the additions with a handheld mixer on low speed an not overwork the potatoes.
Step Five: Transfer and Chill (or Bake Right Away)
Spread the potato mixture into a greased 2-quart casserole dish. If making ahead, cover tightly and refrigerate for up to 48 hours. Otherwise, bake right away.
👉🏻Freezing the Casserole? Mix in an additional ½ cup milk, transfer to a freezer-safe baking dish, cover well, and freeze for up to 1 month.
Step Six: Bake and Serve
Bake at until the top is slightly browned and the center is warmed through. The edges will puff a bit, and your kitchen will smell like buttery heaven.
Recipe Modifications
- Make it Cheesy: Stir 1 cup shredded cheddar into the potato mixture and then top the casserole with an another cup of cheese before baking.
- Loaded Mashed Potato Casserole: Top with cheese and crumbled bacon before baking. Add chopped chives right before serving.
- Egg-Free Option: Simply omit the eggs. The casserole won't puff up as much, but it will still taste rich and creamy.
- Omit the Onions: If you don't care for onions, you can omit altogether or replace the grated raw onion with 2 teaspoons onion powder.
Make-Ahead Tips
This dish was built for planning ahead and designed to reduce stress at the holidays!
- Up to 2 Days in Advance: Assemble, cover, and refrigerate. Let it sit at room temperature for 30-60 minutes and bake for an extra 45-50 minutes.
- Up to 1 Month in Advance: Add an extra ½ cup milk, assemble in a freezer and oven safe baking dish (like a disposable foil baking dish), cover tightly with 2 layers of foil and freeze for up to 1 month. Thaw overnight in the fridge before baking.
- Traveling? Bake at home and keep warm in an insulated casserole carrier. It will keep warm for about an hour.
Serve this Mashed Potato Casserole alongside your holiday favorites like Baked Ham, Roasted Turkey, or even a juicy New York Strip Roast and watch it quietly steal the show. And if your family is anything like mine, don't expect leftovers. xo-Kristen
More Favorite Holiday Side Dishes
- Sweet Potato Casserole
- Classic Bread Stuffing
- Roasted Butternut Squash Salad
- Green Bean Casserole
- Corn Casserole
Mashed Potato Casserole
Video
Ingredients
- 3 pounds russet or Yukon gold potatoes, peeled, and cubed
- 8 ounces full-fat cream cheese, softened
- ¼ cup unsalted butter, melted
- ½ cup full-fat sour cream
- ½ cup milk, any fat percentage
- ½ cup finely chopped yellow onion, optional
- 1 teaspoon kosher salt
- pepper, to taste
- 2 large eggs, lightly beaten
Instructions
- Grease a 9x13-inch casserole dish or 3-quart baking dish generously with butter. Preheat oven to 350℉ (175℃) if baking immediately.
- Place potatoes into a large stock pan. Cover with cold water and add 2 teaspoons kosher salt. Bring the potatoes to a rapid boil, then reduce the heat to medium. Simmer until the potatoes are fork-tender (the chunks should fall apart easily when pieced with a fork.) Drain the potatoes and return to the hot pan. Place over low heat and simmer until all the moisture has evaporated-about 1-2 minutes.
- In a large bowl, mash the hot potatoes by hand with a potato masher. Once mashed.
- Add 8 ounces full-fat cream cheese, ¼ cup unsalted butter, ½ cup full-fat sour cream, ½ cup milk, ½ cup finely chopped yellow onion, 1 teaspoon kosher salt, and a pinch of pepper to the mashed potatoes and mix on low speed using a handheld mixer until combined and fluffy. Whisk 2 large eggs in a small bowl, then add to potato mixture and mix quickly to combine.
- Transfer the potato mixture to the prepared casserole dish, spreading it out into an even layer. If not baking immediately, cover tightly and refrigerate up to 48 hours.
- If baking immediately, bake at 350℉ (175℃) for 20-25 minutes, or until warmed through and slightly browned. If baking after refrigeration, let the casserole sit at room temperature for 30 minutes while the oven preheats, uncover, and bake at 350℉ (175℃) for 45-50 minutes.
Equipment
- 9x13 Casserole Dish (a beautiful dish for oven to table!)
- large stock pan (this one fits a ton)
- potato masher (or use a potato ricer for less lumps!)
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Quick question - it says not to temper the eggs before adding. How do the eggs not cook or curdle in the hot potatoes? Just curious. Thanks!
Hi Shawn! Great questions, but adding the creamed cheese, milk, sour cream, and eggs together cool the potatoes enough, we have not had this issue. If you are concerned, mix the sour cream, milk, butter, cream cheese into the potatoes first, then mix in the eggs. Enjoy!
I made these for Christmas dinner. They were absolutely delicious and a hit with everyone!
Thank you for sharing, Janet!
We had this for dinner tonight and the family all thought it was great! The prep time is a bit more than mash potato but I do understand what an advantage it would be if you prepared it in the morning ready to cook for that nights dinner. The potatoes were definitely still fluffy. I made mine entirely in the instapot so drying out the potatoes after straining was pretty easy. Will definitely keep in mind for when I have guests and prep ahead. Thanks
Excellent! Easy and delicious.
Would this do ok in a roaster oven? I want to make it for Christmas dinner but oven space will be limited
Hi Monica! Yes! Just be sure to follow the instructions for cooking. (Put water in the roaster if called for per your model). Keep in mind it may cook a bit faster as well, so I would be sure to keep a close eye on it.
This was wonderful when I made it for Christmas last year. I did the cheesy variety and added a bit of garlic. Do you think it would turn out well with yukon gold potatoes. My hands are really arthritic this week and they peel more easily
Hi Debbie! I am sorry your hands have been bugging you this week. As for the potatoes, yukon gold will be perfect!
Would it be possible to do this in the instant pot?
Hi Shanna! You can opt to cook the potatoes in the instant pot, using 2 cups of water and 1 teaspoon of kosher salt, and cook for 10 minutes on high pressure with a 10-minute natural pressure release. Then drain the potatoes and process with making the casserole. recipe for the casserole itself will not work in the instant pot unless you used the pot-in-pot cooking method, and for this recipe, I don't recommend that.
What would I adjust the measurements too if using a 5 lb bag of potatoes?
Hi Linda! That is nearly double the recipe, so would need to be baked in 2 casserole dishes or one 6-quart dish. The measurements are not easy to increase evenly since just shy of doubling the recipe, but you would need to use 13 ounces of cream cheese, 1/2 cup butter, 3 eggs, 1 cup of sour cream, 1 large minced onion, just shy of 1 cup of milk, and about 2 teaspoons of salt. Keep in mind you may need to increase the baking time based on the size of your oven.