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My go-to, make-ahead Crockpot Cheesy Mashed Potatoes with Caramelized Onions. Made simply and easily in the crockpot with cream, salted butter, onions, and melty Gruyere cheese. Each bite is perfectly smooth, creamy, and so delicious. This method makes for the creamiest and most flavorful mashed potatoes. You can make these in the crockpot, instant pot, or on the stove top. They’re perfect for making ahead of time for easy entertaining!
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I just could not do Thanksgiving without perfect mashed potatoes. After all, they’re everyone’s favorite side dish, right? My brothers are mashed potato fanatics. They say the only reason they love turkey and gravy is thanks to the forkful of mashers they add with each bite.
And while I definitely have other mashed potato recipes on the site, this is the family favorite. The crew really loves a cheesy, buttery potato with just the right amounts of onions. Not overpowering, but just right.
These are their perfect potatoes. I think I got the ratios just right! They’re now labeled as “fire” mashed potatoes.
Clearly, we love these potatoes.
After many years of trying all the ways to cook my mashed potatoes, I’ve decided that using the slow cooker is my favorite. When in a time crunch, I use the instant pot or stove top, but the crockpot is my ideal cooker.
I do mine a little differently than most.
Here are details
Most recipes for potatoes in the crockpot don’t have you cook the potatoes in water, then drain. They’ll tell you to cook in milk or broth. But I just don’t find that to work as well.
Peel the russet potatoes. I then add the potatoes to the crockpot, add water, add garlic, and salt, then cover and let them slow cook for a few hours or up to all day.
Once the potatoes are fork-tender, I drain them and add them back to the dry, but still hot crockpot bowl. I set the crockpot to low, then cook onions. The key is to allow the potatoes to sit in the hot crockpot to dry off. Reducing the moisture gives you a creamier texture to these tasty potatoes!
While the potatoes sit, I make the onions.
A lot of mashed potato recipes call for onion powder. But I wanted to add a little more of a fresh onion flavor that wasn’t overpowering, but just right.
I love using caramelized onions for an onion flavor that’s more mellow.
I first caramelize them down in a bit of butter. Then I like to add some wine to help them caramelize a little faster. Next, just a little fresh thyme, sage, salt, and pepper. Plus lots of butter, which is key for any good potato dish.
When it comes to mashing the potatoes, I don’t do anything fancy, just mash them with a potato masher and call it a day. But you do you, if you love a super smooth, whipped potato, try using a potato ricer or hand-mixer instead.
Once I have the potatoes mashed, I add cream, sour cream, the caramelized onions, butter and melty gruyere cheese. Continue letting the potatoes cook until the cheese is melted. And that’s it, you’ll have the most perfect, flavorful, and creamiest mashed potatoes.
Classic, but with amazing flavor and cheesiness.
Serve these up warm with a little added sage for color.
I’m excited to not only share this recipe with you guys but also with family and friends. My brothers have all agreed, these are one of their favorite potato dishes.
When you win over the brothers, all is good!
The next question is, what will you be pairing these crock pot mashed potatoes with? The obvious answer for Thanksgiving is turkey. But come December, over here it will be my roasted beef tenderloin. Great with steak, pork, or any weeknight dinner.
Looking for other easy Thanksgiving sides?? Here are my favorites:
Crispy Parmesan Thyme Sweet Potato Stacks
Sweet Potato Casserole with Sweet ‘n’ Savory Bacon Pecans
Easiest No-Boil Brie Mac and Cheese
Lastly, if you make these Crockpot Cheesy Mashed Potatoes with Caramelized Onions, be sure to leave a comment and/or give this recipe a rating! Above all, I love to hear from you guys and always do my best to respond to each and every comment. And of course, if you do make this recipe, don’t forget to tag me on Instagram! Looking through the photos of recipes you all have made is my favorite!
Crockpot Cheesy Mashed Potatoes with Caramelized Onions
Ingredients
- 5 pounds Russet or Yukon Gold potatoes, peeled and quartered
- 2 cups water
- 2-4 cloves garlic
- 2 teaspoons kosher salt
- 1 stick (1/2 cup) salted butter
- 1-2 yellow onions, thinly sliced or chopped
- 1/4 cup dry white wine
- kosher salt and black pepper
- 1 tablespoon chopped fresh thyme
- 8 sage leaves
- kosher salt and black pepper
- 1/2 cup sour cream
- 1/2 – 1 cup heavy cream
- 1 1/2 cups shredded gruyere cheese
Instructions
Crockpot
- 1. In the bowl of your crockpot, combine the potatoes, water, garlic, and salt. Cover and cook on high for 4 hours or on low for 6-8 hours, until the potatoes are fork tender. Set the crockpot to low or warm. 2. Drain the potatoes, then add them back to the crockpot. Let sit, uncovered while you caramelize the onions. 3. Melt together 4 tablespoons butter and the onions in a large skillet over medium heat. Cook, stirring occasionally until softened, about 10 minutes. Add the wine and continue to cook another 5 minutes until the onions are deeply caramelized.4. Add 4 tablespoons butter, the thyme, and sage, and season with salt and pepper. Cook another 2 minutes, then remove from the heat.5. Mash the potatoes with a masher. Add the cream and sour cream, adding more cream until your desired consistency is reached. Season the potatoes with salt and pepper. Stir the onions in with the butter and cheese, cover, and cook another 15 minutes, or until the cheese is melted and creamy. Keep the potatoes covered, on warm, for up to 4 hours.
Instant Pot
- 1. In the bowl of your instant pot, combine the potatoes, water, garlic, and salt. Cover and cook on high pressure for 14 minutes. Release the steam, drain the potatoes, then add them back to the instant pot. 2. Set the instant pot to warm. Let sit, uncovered while you caramelize the onions. 3. Melt together 4 tablespoons butter and the onions in a large skillet over medium heat. Cook, stirring occasionally until softened, about 10 minutes. Add the wine and continue to cook another 5 minutes until the onions are deeply caramelized.4. Add 4 tablespoons butter, the thyme, and sage, and season with salt and pepper. Cook another 2 minutes, then remove from the heat.5. Mash the potatoes with a masher. Add the cream and sour cream, adding more cream until your desired consistency is reached. Season the potatoes with salt and pepper. Stir the onions in with the butter and cheese, cover, and cook another 15 minutes, or until the cheese is melted and creamy. Keep the potatoes covered, on warm, for up to 4 hours.
Stove
- 1. In a large dutch oven, combine the potatoes, 6 cups water, the garlic, and salt. Bring to a boil over medium-high heat and cook 20-25 minutes, until the potatoes are fork tender. Drain the potatoes, then add them back to the pot.2. Finish as directed through step 3.
Nutrition
Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Did you make this recipe? Please rate & comment below.
Do you peel and cut potatoes or leave them whole?
Hey Brit,
Yes, the recipe calls for 5 pounds of potatoes peeled and quartered. Please let me know if you have any other questions, I hope this recipe turns out well for you! xx
What is a good substitution for Gruyere cheese? I making this. Thank you for this recipe. Can’t wait to try it
Hey Holly,
Any cheeses you like will work here, fontina would be a great option! Please let me know if I can help in any other way, I hope you love this recipe! xx
If prepping a few days early, how do you recommend storing and reheating?
Hey Hailey,
You can follow the make ahead instructions here:
https://www.halfbakedharvest.com/make-ahead-roasted-garlic-mashed-potatoes/
Please let me know if you have any other questions, I hope you love this recipe! xTieghan
Cannot WAIT to try this! Has anybody ever tried adding bacon to this?
Thanks so much Emily! Bacon would probably be delicious:) I hope you love the recipe! xT
I printed this recipe and we will give it a try this Thanksgiving; we’re not even having turkey this year; don’t feel like it. Thank you for sharing!
Thanks so much! I hope you love the recipe!! xT
For those of us who can’t have wine in the house…what else could I caramelize with?
Chicken broth
Hey Ashley,
You could use broth or apple cider to caramelize the onions. Please let me know if you have any other questions! xT
Beautiful, original twist on classic mashed potatoes, and the sage and white wine are great compliments. I don’t love onions, but I put them on the side for everyone else to add as they wished. Was a very nice side to a cozy chicken and mushroom dish!
Hey Aline,
I truly appreciate you giving this recipe a try and sharing your feedback, love to hear that it was enjoyed!❄️ xx
“Nice” How sweet eats copycat recipe lol (not first time that happens though)
Love that this can be done in the crockpot to be super easy for the holidays. Looks so delicious! Always been my favorite side too!
xo Jessica
an indigo day
Thanks so much Jessica, I hope you love the recipe! xx
YES! This was the recipe I was waiting on for Thanksgiving. Your Caramelized Onion recipes are LEGENDARY 🙂 Family still talks about your scalloped potatoes with them in it, they add such a unique and delicious twist. Just have to take your time and cook them long and slow! Thanks for your amazing recipes day after day!
Wow! Thanks so much for your kind message Lisa:) I hope your family loves this recipe! Happy Thanksgiving! xT
What happens to the garlic that goes in with the potatoes while they cook? Does it get tossed or mashed in with the potatoes?
Hey Johanna,
If you like extra garlic flavor, you an mashed them with the potatoes, otherwise you can toss them! Please let me know if you have any other questions! xTieghan
I would assume it should be discarded, having done its job in flavoring the potatoes as they boil.
Would love to make this for Thanksgiving… I have 17 people coming and would like to make these ahead of time like in the morning of and then reheat when needed at about 4pm is that do-able?
Hey Elaine,
You can fully make them and then just set your crockpot to warm, that will be perfect! Please let me know if you have any other questions! xT
I’m trying to decide between this recipe and Slow Cooker Cheesy Garlic Herb Mashed Potatoes. This one says water is best for creamy potatoes, the other one says milk/cream. What’s the main difference in the final product?
Hey Dana,
The cheesy garlic and herb mashed potatoes are using cream to infuse all of the potatoes with the flavors from which they cooked in. It really depends if you would prefer more herby or more oniony potatoes, both recipes are family faves:) xx
thanks – wish I had time to experiment with cooking in milk/cream vs water. I may just have to do some taste testing this weekend. 😉
I’ve been waiting for your debut of this recipe!! So excited to make these for Thanksgiving!
Lol thanks so much Maura!! I hope you love the recipe! Happy Thanksgiving! xT
CROCK POT MASHED POTATOES SOUNDS LIKE TOTALLY DELICIOUS…GOING TO TRY FOR THANKSGIVING..THANKS
Thanks Joy!! I hope you love this recipe! xx