These Vegan Caramelized Onion Mashed Potatoes are no ordinary potato recipe! I may just go far enough to say they are truly the *best* creamy mashed potatoes I have ever made. The best part? Only 8 ingredients are needed for the easiest dairy-free & gluten-free side dish.
*Recipe originally shared November 2018 and updated November 2022*
Does anyone else agree that the best part of Thanksgiving is all the sides?! Even before I was a vegetarian, I always counted down the days until I could eat my body weight in mashed potatoes, stuffing, roasted vegetables, and pecan pie.
Luckily, making homemade french onion mashed potatoes that are VEGAN and CREAMY is super easy. It really all comes down to how you cook the potatoes which is why I will be sharing all my tips & tricks for the best fluffy dairy-free mashed potatoes below.
Mashed potato ingredients:
Tips to make the best vegan mashed potatoes
There are a few tips and tricks I've learned from making homemade mashed potatoes for Thanksgiving these past few years. It's only fair I take the majority of this blog post to walk you through how to make creamy mashed potatoes.
Tip 1: Always peel potatoes
While the skin on potatoes is certainly nutritious, when it comes to mashed potatoes using potato skin ultimately leads to a less ideal texture. For creamy potatoes, I recommend peeling those potatoes!
Tip 2: Use starchy potatoes
I use about 75% Russet potatoes and about 25% Yukon potatoes for my perfect mix of Mashed Potatoes.
Russet potatoes are starchy potatoes, have a very neutral taste, and absorb the butter perfectly when mashing. However, adding in a few Yukon potatoes adds a little more flavor than just using Russet potatoes.
Essentially, starchy potatoes have less moisture and low sugar levels making them ideal for mashing & frying. I do not recommend using waxy potatoes for this recipe such as red bliss, baby potatoes, or fingerling potatoes.
Tip 3: Boil potatoes in large chunks & not for too long
Make sure to boil your potatoes in large chunks so they don't absorb too much water. Absorbing too much water leads to less flavorful and watery mashed potatoes.
This also means not overcooking your potatoes. I test my potatoes with a fork as I am cooking and as soon as they are pierceable all the way through they are ready.
Do not cook potatoes until they are mushy and falling apart or they will be too watery.
Tip 4: Room temperature butter is best
I like to use room temperature for mashed potatoes so that the potatoes can fully absorb all the butter. Also, make sure to mash the butter and potatoes together while the potatoes are still hot for the best results!
This means letting the vegan butter sit at room temperature while the potatoes are cooking so it is not cold.
Tip 5: Don't over-mash your potatoes.
Seriously, having chunks is good! If you mash potatoes for too long, they will release too much starch and get a gummy consistency. YUCK. I recommend using a Potato Masher over a blender as well!
Tip 6: Just a little bit of high-fat vegan milk is needed
Have you ever made mashed potatoes that are too dry and tried to solve it by adding more milk? Well, I am here to tell you that's a no-no. Milk is just going to dry the potatoes out more and make them watery.
What is the best milk substitute for mashed potatoes? Anything high in FAT!
When it comes to milk, I even recommend sticking to high-fat milk such as coconut milk in this recipe vs almond milk or soy milk for that very reason. Oh and you can totally just leave out the milk and replace it with more vegan butter.
Tip 7: Don't be afraid to add a lot of salt and pepper.
I realize that with mashed potatoes, the ideal salt-to-potato ratio really varies by person so I didn't include any definitive amounts.
One thing that helps is making sure to boil your potatoes in really salty water as this adds a ton of flavor to the potatoes before you have to salt at the end.
Another fun idea? Swap out normal salt for garlic salt for mashed potatoes with caramelized onions that also are full of garlic flavor!
How to make caramelized onions
To make caramelized onions, I heat the vegan butter in the pan first. Once the vegan butter has melted, I add in the chopped onions. I always make sure to mix my onions frequently while they are cooking until they are soft and brown.
How long does it take to caramelize onions?
The truth behind making caramelized onions is that they take time. If you see a recipe calling for just 10-15 minutes of time- that is really just sautéed onions being made. Some people may say 40 minutes isn't enough for a true caramelized onion (some recipes call for up to 4 hours of time!), but I find that I love the flavor of the onions after cooking for this amount of time.
Since I know we are trying to make potatoes that taste good and aren't too complicated, I left this recipe open-ended to call for 20-40 minutes to caramelize the onions. Ultimately, the flavor deepens the longer you cook the onions, so do what works best for you!
What Makes Caramelized Onions Sweet?
When you think of caramelized onions and the sweetness behind them, you may think sugar gets added during the cooking process.
However, it's really just the caramelized onions breaking down the natural sugars into smaller molecules that brown the onions and give them a sweeter flavor.
I mean, how cool is it that a naturally sharp & pungent ingredient can turn sweet just with a little heat? Just another reason I love geeking out about food science!
FAQ & Troubleshooting:
Can I make vegan mashed potatoes without butter or oil?
I really don't recommend it! As mentioned before, fat is what leads to creamy fluffy mashed potatoes and too much milk will actually make these potatoes too dry.
If you have to, I would only recommend subbing vegan butter for canned coconut milk so there is enough fat in this recipe
Why are my mashed potatoes gummy?
This is usually due to two things. One is using the wrong potatoes. Waxy potatoes will lead to a gummier consistency.
The second is over-mashing potatoes. If you mash your potatoes too long excess starch will get released which will lead to gummy potatoes.
Is it possible to prep mashed potatoes ahead of time?
Yep! These potatoes reheat nicely and can even be made a day in advance when prepping for any Holiday celebrations.
They truly are best right after making, but still taste great the next day! Also, leftover mashed potatoes can be stored in a closed container in the fridge for 3-4 days.
How should I serve vegan mashed potatoes?
I love serving these mashed potatoes for Thanksgiving along with my favorite Vegan Stuffing, Miso Brussel Sprouts, Green Bean Almondine, and my Vegan Acorn Stuffed Squash. I also love them with mushroom gravy on top!
However, these mashed potatoes really make the perfect vegan side dish for any occasion and are great for Thanksgiving, Christmas, or a fancy dinner at home.
These Vegan Caramelized Onion Mashed Potatoes are honestly the BEST side dish full of french onion flavor & dairy-free ingredients. They are always a staple at our Thanksgiving dinner and are one of those recipes people literally say "I can't believe this is vegan!?". Enjoy!
More vegetarian side dishes you will love:
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Vegan Caramelized Onion Mashed Potatoes
- 6-7 medium peeled potatoes a mix of 75% russet and 25% yukon potatoes works best
- 6-8 Tablespoons vegan butter make sure the butter is room temperature
- 2 Tablespoons full-fat coconut milk can be replaced with additional 2 Tbsp of vegan butter
- 1 teaspoon garlic powder
- salt & pepper to taste
- fresh thyme optional
- 1 large thinly sliced yellow onion
- 2 Tablespoons vegan butter or oil
- salt & pepper to taste
- Before starting, peel your potatoes and cut into large but equal sized pieces. Slice your onions into thin long slices and set aside.
- Add the peeled potatoes to a strainer and rinse to remove some of the starch. Then, add the potatoes to a large pot and fill the pot with cold water until the potatoes are just covered by about ½" of water. Add a generous amount of salt to the water until the water tastes salty.
- Bring the pot of potatoes to a boil and cook for 15-20 minutes until you can pierce the potatoes with a fork/knife and they are the same consistency all the way through. You don't want to overcook your potatoes or the mashed potatoes will be too watery, so I recommend checking at the 12 minute mark to be safe.
- While the potatoes are cooking, caramelize the onions. Add 2 Tbsp of vegan butter/oil to a frying pan and turn on the burner. Once the butter is bubbling and melted, add in the onion slices. Pan fry at low heat until onions are browned; around 20-40 minutes depending on preference. Stir frequently so that the onions do not burn. Once the onions are done, season with salt and pepper to your liking and set aside.
- As soon as the potatoes are cooked, strain and add back to the pot. Use a potato masher to roughly mash the potatoes while still hot.
- Once the potatoes are somewhat mashed, add in 6-8 Tbsp of room temperature/melted butter to the pot and continue mashing until the potatoes are mostly smooth with some chunks. How large your potatoes are and how buttery you like your mashed potatoes will determine how much butter you use, so feel free to add in more or less to your liking! For creamier mashed potatoes, add in the 2 Tbsp of coconut milk at this time as well. Season with the garlic powder, fresh thyme, and additional salt & pepper until your desired flavor is reached. As a final step, gently fold in the caramelized onions.
- Top with additional fresh thyme or a homemade gravy and serve warm. Enjoy!
- I use about 75% Russet potatoes and about 25% Yukon potatoes for my perfect mix of Mashed Potatoes.
- Make sure to boil your potatoes in large chunks so they don't absorb too much water.
- I like to use room temperature for mashed potatoes so that the potatoes can fully absorb all the butter. Also, make sure to mash the butter and potatoes together while the potatoes are still hot for the best results!
- Using a Potato Masher is the best way to enjoy potatoes that are not over-mashed.
- Mashed potatoes are best enjoyed on the day the potatoes are cooked. If you are making an hour or two ahead of eating make sure to keep warm and covered so the potatoes do not dry out.
- Leftovers can be stored in a closed container in the fridge for 3-4 days.