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. They’re perfect for making ahead of time for easy entertaining!
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 crockpot is my favorite. When in a time crunch, I use the instant pot or stove, 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.
I 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 even creamy, tastier 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 masher and call it a day. But you do you, if you love a super smooth, whipped potato, try using a potato ricer instead.
Once I have the potatoes mashed, I add cream, sour cheese, the carmelized 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 cheesy potatoes with? The obvious answer for Thanksgiving is turkey. But come December, over here it will be my roasted beef tenderloin.
Looking for other easy Thanksgiving sides?? Here are my favorites:
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
Calories Per Serving: 521 kcal
Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
- 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
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- 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.
- 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.
- 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.