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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.
Hi I don’t have a hand held mixer can I mix everything by hand or will that be too hard ? I can also use my Kitchenaid
Hi Kris! I would actually consider combining the sour cream, cream cheese, eggs, and seasonings in the kitchen aid mixer until creamy and smooth. Then fold in the mashed potatoes--that will keep the potatoes from getting gummy but ensure the casserole is well combined. Enjoy and Happy Thanksgiving!
Hello! Can I make this with instant potato flakes? If so, how many cups of potatoes would I need before I add the additional ingredients?
Hi Jen! I have never tried making this with Instant Potato flakes, but in theory, it should work. 3 pounds of potatoes equals about 6 cups of mashed potatoes, which would be the same as using 6 cups of potato flakes. I would suggest rehydrating them by bringing 9 cups of water to a boil, remove from heat, add 6 cups of potatoes flakes and then add the remaining ingredients to that mixture. I hope that helps!
Hi. Can I Make 1 1/2 this recipe and still use a 9x13 casserole? Thank you
Hi Kathy! If you don't have a 2-quart dish, a 9x13 dish will work. You may need to decrease the baking time by 10 minutes.
. Hi. I meant that I wanted to increase it by 1/2. Would that be too much to put in the 9 x 13 casserole? Thank you for your response. Greatly appreciated.
Gotcha! Sorry I misunderstood--I hadn't had my coffee yet. LOL! It will be a tight fit if your casserole dish is not deep. If on the deeper side, you will be just fine 🙂 You may want to increase the baking time by 10 minutes as well.
Thank goodness I have an industrial immersion blender. After reading reviews, suggestions and concerns I went ahead and added the eggs last - against my better judgement. Sure enough I ended up with scrambled eggs throughout my mashed potatoes. I was able to blend them up but the mashed potatoes lost their lovely consistency. At least the taste is still there.
Hi Lydia! I have never had an issue adding eggs directly to the potato mixture after adding the cream cheese, etc. But I hate hearing you had this problem. I added a note about how to temper eggs to prevent this from occurring. Thanks for sharing.
A very good recipe, easy to make and extremely tasty. I admit I couldn't resist and put parmigiano on top (I love it). Otherwise, I followed the recipe exactly.
Thank you
Nothing wrong with a little extra parmesan 🙂 I am thrilled to hear you enjoyed.
Can I use powdered onion instead of fresh or dried flakes? How much?
Absolutely! I would add no more than 2 teaspoons of onion powder.
I usually make a similar recipe with bacon and have never tried to use eggs. My family loved it. Thank you!
You are welcome, Nancie! I am so glad you gave it a try and enjoyed it. Thanks for taking the time to leave a comment and review 🙂