Leek mashed potatoes turn a familiar comfort food into a side dish worth savoring at any dinner. Roasted leeks, Yukon gold potatoes, garlic, butter, and thyme blend for a smooth, flavorful mash that feels both classic and refined.
If you love cooking with leeks, try my Puff Pastry Chicken Pot Pie with Bacon and Leeks next.
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I love the balance leeks bring to mashed potatoes—their mild, onion-like flavor adds depth without overpowering the dish. Roasting them first brings out a gentle sweetness that complements the butter and garlic perfectly. The thyme-infused cream ties everything together, creating layers of flavor that make these mashed potatoes anything but ordinary. This is a recipe that transforms simple ingredients into something truly special.
Why This Leek Mashed Potatoes Recipe Works
- Perfect for the Holidays – A comforting yet sophisticated side dish that fits seamlessly into any Thanksgiving, Christmas, or festive dinner menu.
- Delicious Leek Recipe – The roasted leeks bring a mild, savory flavor and an opportunity to learn how to cook with this underrated ingredient.
- Creamy, Rich Texture – Butter and infused cream create a smooth, velvety mash that’s indulgent without being heavy.
Can you put leeks in mashed potatoes?
Yes, leeks make a wonderful addition to mashed potatoes. They add a gentle savoriness that enhances the flavor without overpowering it, and when roasted, they develop a soft, aromatic depth that blends beautifully into the creamy potatoes. The result is a mash that feels more nuanced and restaurant-worthy.
Tools You’ll Need
- Large pot
- Large bowl
- Baking pan
- Small saucepan
- Fine mesh sieve
- Potato ricer
- Spatula
- Measuring cups
- Measuring spoons
- Cutting board and knife
Ingredients You Will Need for Leek Mashed Potatoes
Here is a breakdown of what you will need to make this potato leek mash. For actual measurements, see the recipe card at the end of this post.
- Yukon Gold Potatoes – I love using Yukon golds for their naturally buttery flavor and creamy texture, which make for an ultra-smooth mash.
- Leeks – Their mild onion flavor adds depth and a subtle sweetness that balances the richness of the potatoes.
- Kosher Salt (Diamond Crystal) – Seasoning properly is key; Diamond Crystal gives me more control over the flavor.
- Avocado Oil – Ideal for roasting leeks since it has a high smoke point and a clean, neutral taste.
- Whole Milk – Adds lightness to the mash while keeping the texture silky.
- Heavy Cream – Provides richness and body that take these mashed potatoes beyond basic.
- Garlic – Roasting it right in the cream infuses every bite with gentle, aromatic flavor.
- Fresh Thyme – Its earthy, floral notes pair beautifully with the leeks and butter.
- Whole Black Peppercorns – Infuses the cream mixture with subtle spice without overpowering the dish.
- Salted Butter – Melted and folded in for that rich, luxurious finish that defines great mashed potatoes.
How To Make Leek Mashed Potatoes
Below is a summary of how to make mashed potatoes with leeks. For a complete and detailed list of steps, see the recipe card at the end of this post.
How to Clean Leeks
Leeks tend to trap dirt and grit between their layers, so it’s important to clean them well before cooking. I trim the dark green tops, slice the leeks in half lengthwise, and rinse them under cold running water, gently fanning out the layers to remove any hidden debris. Once clean, I pat them dry before roasting.
Roast the Leeks
If you’re planning to make my Five-Spiced Short Ribs, this is a great time to roast the leeks — the oven temperature drops to 300°F, the same temperature needed to finish braising the short ribs.
I start by coating the leeks in avocado oil and seasoning them lightly with salt. They roast at 400°F until golden and tender, about 20 to 25 minutes.
Once they’re beautifully caramelized, I flip them, reduce the heat to 300°F, and bake for another 5 minutes until soft. After cooling, I finely chop the leeks, reserving a small spoonful for garnish later.
Infuse the Cream Mixture
While the leeks roast, I make the infused cream. In a small saucepan, I combine milk, heavy cream, garlic, thyme, and whole peppercorns. I let it gently simmer, then cover it so the flavors can steep. This mixture adds incredible depth to the leek mashed potatoes and ties all the ingredients together.
Cook the Potatoes
I peel and slice the Yukon gold potatoes, then soak them in ice water for about 30 minutes to remove excess starch.
After draining, I add them to a large pot with cold water and a generous pinch of salt. I bring them to a boil, then simmer until the potatoes are fork-tender—usually around 15 minutes.
Mash and Combine
While the potatoes are still hot, I rice them into a large mixing bowl. Warm melted butter goes in first, folded in gradually so it fully absorbs. Then I strain the infused cream mixture through a fine mesh sieve, adding it in stages until the mash is silky and smooth.
Finally, I fold in the roasted leeks, tasting and adjusting with more salt if needed.
Serve
I spoon the mashed potatoes and leeks into a serving bowl and top them with a drizzle of melted butter and the reserved roasted leeks. The result is smooth, rich, and full of aromatic flavor—comforting enough for everyday dinners yet elegant enough for any special occasion.
Tips and Tricks
- Soak the potatoes. Letting the sliced potatoes sit in ice water helps remove excess starch and prevents a gummy texture.
- Roast the leeks until golden. This step brings out their sweetness and gives the mash a deeper, more complex flavor.
- Infuse the cream gently. Keep the milk and cream over low heat so the garlic and thyme have time to release their flavor without curdling the mixture.
- Mash while the potatoes are hot. Hot potatoes absorb butter and cream more easily, resulting in a smooth, velvety texture.
- Strain the infused cream. Removing the solids ensures a silky consistency that blends seamlessly into the mashed potatoes.
- Season gradually. Add salt in stages and taste as you go to achieve balanced seasoning without over-salting.
- Make ahead with care. These mashed potatoes can be made a day in advance. Reheat over low heat and stir in a splash of warm milk to restore their creamy texture.
What to Serve with Leek Mashed Potatoes
- Five-Spiced Short Ribs – The warm, aromatic braise begs for a creamy base; leek mashed potatoes soak up the sauce and give a soft counterpoint to tender beef.
- Baked Salmon – The bright tomato and zesty scallion sauce meet their match in the silky potatoes; the leeks echo the allium notes and round out the acidity.
- Roasted Chicken Recipe – Juicy roast chicken and its pan juices pair naturally with a buttery mash; garlic and thyme in the potatoes bridge the flavors for a complete dinner.
Frequently Asked Questions
What is the trick to good mashed potatoes?
The trick to good mashed potatoes is starting with the right potato and handling it while it’s still hot. Yukon golds are naturally creamy and absorb butter and cream beautifully, but mashing them cold can make the texture gummy. Working quickly and adding warm butter and infused cream ensures a smooth, velvety finish every time.
How should I clean the leeks before cooking?
Leeks often hold dirt between their layers. Slice them in half lengthwise, rinse thoroughly under running water, and gently separate the layers to remove any grit before roasting.
Can I make these leek mashed potatoes ahead of time?
Absolutely. Prepare them up to a day in advance, let them cool, then cover and refrigerate. When ready to serve, reheat gently with a splash of milk to restore their creamy texture.
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Mashed Potatoes with Leeks
Equipment
- Large pot
- Large Bowl
- Baking pan
- Fine Mesh Sieve
- Potato Ricer
- Spatula
- Measuring cups
- Measuring spoons
- Cutting board and knife
Ingredients
- 2 pounds yukon gold potato
Leeks
- 2 large leeks, white and light green parts only, halved
- kosher salt, to taste, Diamond Crystal
- avocado oil
Butter Cream
- ½ cup whole milk
- ¼ cup heavy cream
- 1 head garlic, ¼ top removed
- 8 sprigs fresh thyme
- ½ teaspoon whole black peppercorn
- 1-1¾ teaspoon kosher salt, Diamond Crystal, to taste
- ½ cup salted butter, melted, kept warm
Garnish
- 1½ tablespoons salted butter, melted
- reserved roasted leek
Instructions
- Preheat oven to 400°F.
- Peel and slice potatoes. Transfer to a large bowl then fill with water and enough ice cubes for ice water. Set aside for 30 minutes.
- Coat leeks with avocado oil then lightly salt to taste. Roast leeks in a prepared baking pan in the oven until lightly golden brown, 20-25 minutes. Once leeks are lightly golden (flat side down), flip leeks then drop oven temperature to 300°F and continue to bake for 5 minutes or until leeks are softened. Once cooled, finely chop then set aside (can set reserve 1 teaspoon for garnish, if desired.)
- Meanwhile, add whole milk, cream, garlic (cut side faced down), thyme, and black peppercorns to a small saucepan. Bring the mixture to a simmer over medium heat. Drop the heat to low, cover the saucepan and cook for 5 minutes. Remove from heat and leave covered; mixture will continue to steep. (Just before adding the milk mixture to the potatoes, make sure the mixture is warm, reheat if needed.)
- Drain water then place potatoes in a large pot. Add water about 1 inch above potatoes. Add 2 teaspoons kosher salt. Bring to a boil then lower to a simmer. Cook for 13-16 minutes, or until potatoes are fork-tender.
- It's important to do the next step quickly and while potatoes are hot. Doing this with cold potatoes will potentially result in gummy mash. Wear oven mitts to protect your hands while handling hot potatoes.
- Rice potatoes into a large mixing bowl. Pour half of the warm, melted butter into the potatoes and mix with a spatula until incorporated. Repeat until all of the butter is added.
- Strain the milk mixture into a fine mesh sieve and into a measuring cup. Pour half of the cream mixture and start with 1 teaspoon of kosher salt. Mix until liquid is fully incorporated and smooth before adding more. Repeat with with remaining cream. Fold in the chopped leeks. Adjust seasoning with salt, if necessary.
- Transfer mashed potatoes to a bowl and garnish with more melted butter reserved leeks. Enjoy!
- Potatoes can be made 1 day ahead. Allow potatoes to come to room temperature, cover and chill. Reheat over medium heat and add more milk to thin out, if needed.
