There's something magical about the sweet, rich flavor of caramelized onions meeting creamy, buttery mashed potatoes. This Caramelized Onion Mashed Potatoes Recipe transforms an ordinary side dish into something your family will request again and again. I've been making this recipe for years, and it never fails to steal the show at dinner parties.
What makes this dish special? It's the perfect balance of sweet caramelized onions and smooth, velvety potatoes that creates comfort food at its finest. Whether you're planning a holiday feast or just want to make Tuesday night dinner feel special, this Caramelized Onion Mashed Potatoes Recipe delivers restaurant-quality results right in your kitchen.

What Makes This Side Dish a Family Favorite
Traditional mashed potatoes are great, but adding caramelized onions takes them to a whole new level. The slow-cooked onions develop a natural sweetness that pairs beautifully with the rich, creamy texture of properly mashed potatoes. This savory mashed potato side works perfectly alongside roasted chicken, grilled steak, or even as a vegetarian main course option.
The beauty of this Caramelized Onion Mashed Potatoes Recipe lies in its simplicity. You don't need fancy ingredients or complicated techniques. Just good potatoes, butter, cream, and the patience to let those onions work their magic. The result is a dish that tastes like you spent hours in the kitchen, even though the actual hands-on time is minimal. This comfort food potato recipe has become my go-to for Thanksgiving, Christmas dinners, and any time I want to impress guests without stress.
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Ingredients
For the Mashed Potatoes:
- Yukon Gold potatoes
- Heavy cream
- Butter (unsalted)
- Salt
- Black pepper
- Garlic cloves (optional)
For the Caramelized Onions:
- Salt
- Yellow onions
- Butter
- Olive oil
- Sugar (optional)
- Fresh thyme leaves

See recipe card for quantities.
Instructions
Caramelize the Onions First
- Heat a large skillet over medium heat and add 3 tablespoons butter with 1 tablespoon olive oil.
- Add the thinly sliced onions and stir to coat them in the fat.
- Sprinkle with a pinch of salt and the optional sugar.
- Cook for 25-30 minutes, stirring every 5 minutes, until the onions turn golden brown and sweet.
- Add fresh thyme during the last 5 minutes of cooking.
- Remove from heat and set aside; this can be done ahead of time.
Pro Tip: Don't rush this step. The key to perfect caramelized onions is patience and medium heat. Too high, and they'll burn; too low, and they'll steam instead of caramelize.
Prepare the Potatoes
- Peel the potatoes and cut them into 2-inch chunks for even cooking.
- Place potato chunks in a large pot and cover with cold water by 1 inch.
- Add 1 tablespoon of salt to the water.
- Bring to a boil over high heat, then reduce to medium and simmer for 15-18 minutes.
- Test doneness by piercing with a fork; they should fall apart easily.
- Drain the potatoes thoroughly in a colander and let them steam dry for 2 minutes.
Important: Starting potatoes in cold water ensures they cook evenly throughout. Hot water cooks the outside too fast, leaving the centers hard.
Create the Creamy Base
- Heat the heavy cream and 6 tablespoons butter in a small saucepan over low heat until the butter melts.
- Add the minced garlic to the cream mixture and let it infuse for 2 minutes.
- Keep the mixture warm but not boiling.
- Return the drained potatoes to the pot.
- Start mashing with a potato masher until no large lumps remain.
- Gradually add the warm cream mixture while continuing to mash.
- Fold in three-quarters of the caramelized onions, reserving some for topping.
Expert Insight: Warm cream is essential. Cold cream will make your mashed potatoes gummy and dense instead of light and fluffy.
Final Assembly and Serving
- Serve immediately while hot and creamy.
- Taste and adjust seasoning with salt and freshly ground black pepper.
- Transfer the creamy onion mashed potatoes to a serving bowl.
- Top with the reserved caramelized onions.
- Add a pat of butter on top for extra richness.
- Garnish with additional fresh thyme if desired.
Expert Cooking Tips
- Temperature Control is Everything Never let your cream mixture boil. Keep it at a gentle simmer or just warm. Boiling cream can cause it to separate and create an oily texture in your finished dish. The same goes for reheating; always use low heat.
- Choose the Right Masher A traditional potato masher gives you the best control over texture. Avoid using a food processor or blender, which will overwork the starches and create a gluey, paste-like consistency. For this Caramelized Onion Mashed Potatoes Recipe, you want some texture, not baby food.
The Make-Ahead Strategy
- Caramelize your onions up to 3 days ahead and store them in the fridge
- Cook and mash potatoes up to 2 hours before serving
- Keep them warm in a slow cooker on low heat, adding a splash of cream to maintain moisture
- Reheat gently on the stovetop with additional butter if needed
- Salt at Every Stage Season the cooking water generously, then taste and adjust after mashing. Potatoes absorb a lot of salt, so what seems like enough rarely is. This layered seasoning approach ensures every bite is flavorful.
- Don't Skip the Steam-Dry Step After draining, let those potatoes sit in the colander for a minute or two. This evaporates excess water, preventing watery mashed potatoes. Extra moisture is the enemy of creamy texture.
- Butter Before Cream Some chefs swear by adding butter to the potatoes first, then gradually adding cream. The fat from the butter coats the starch molecules, preventing them from becoming gluey when you add liquid.
Recipe Variations & Substitutions
Dietary Modifications
- Vegan Version Replace butter with vegan butter or olive oil, and swap heavy cream for full-fat coconut milk or cashew cream. The caramelized onions still provide incredible flavor, and you won't miss the dairy. Add nutritional yeast for a savory, cheese-like depth.
- Lower-Calorie Option Use chicken or vegetable broth instead of cream, and reduce the butter to 3 tablespoons. You'll sacrifice some richness, but the caramelized onions still make this a standout side. Greek yogurt can also replace some of the cream for tang and protein.
- Keto-Friendly Alternative Replace potatoes entirely with cauliflower for a low-carb version. Roast the cauliflower first for deeper flavor, then mash with butter, cream, and your caramelized onions. It's not quite the same, but it satisfies the craving.
Flavor Variations
- Garlic Herb Version Double the garlic and add fresh rosemary, sage, or chives along with the thyme. These herbs complement the sweet onions perfectly and add complexity to your easy mashed potato upgrade.
- Cheese Addition Fold in 1 cup of shredded Gruyère, sharp cheddar, or Parmesan cheese after mashing. The cheese melts into the hot potatoes, creating an ultra-indulgent side dish. This works especially well for this Caramelized Onion Mashed Potatoes Recipe at holiday gatherings.
- Bacon Enhancement Cook 6 strips of bacon until crispy, crumble them, and fold into the mashed potatoes along with the onions. Use 2 tablespoons of the bacon fat in place of some butter for smoky depth.
- Balsamic Twist Add 1 tablespoon of balsamic vinegar to the onions during the last few minutes of caramelizing. This adds a subtle tang that balances the sweetness.
Equipment Recommendations
- Large heavy-bottomed pot ; Essential for even cooking of potatoes without hot spots
- Cast-iron or stainless steel skillet ; Best for caramelizing onions evenly without burning
- Potato masher ; Creates the perfect creamy-yet-textured consistency
- Fine-mesh strainer or colander ; Drains potatoes thoroughly for fluffier results
- Wooden spoon ; Perfect for stirring onions without scratching your pan
- Small saucepan ; For warming cream and butter mixture
Budget Alternative: If you don't have a potato masher, a large fork works in a pinch, though it takes more effort. A ricer creates ultra-smooth results but removes texture, which isn't ideal for this rustic Caramelized Onion Mashed Potatoes Recipe.
Storage & Meal Prep Tips
Refrigerator Storage
- Transfer cooled mashed potatoes to an airtight container and refrigerate for up to 4 days. Press plastic wrap directly onto the surface before sealing to prevent a skin from forming. When reheating, add 2-3 tablespoons of cream or milk to restore the creamy texture.
Freezing Instructions
- These creamy mashed potatoes with caramelized onions freeze surprisingly well. Portion them into freezer-safe containers, leaving half an inch of space at the top for expansion. Freeze for up to 2 months. Thaw overnight in the refrigerator, then reheat gently on the stovetop, stirring frequently and adding extra butter or cream as needed.
Make-Ahead Strategy
- For stress-free entertaining, make this Caramelized Onion Mashed Potatoes Recipe up to 2 days ahead. Store the mashed potatoes and caramelized onions separately. When ready to serve, reheat the potatoes with a splash of cream, then fold in the onions and warm everything together.
Reheating Methods
- Stovetop: Best method. Heat over low, stirring frequently and adding liquid as needed. Microwave: Use 50% power in 1-minute intervals, stirring between each. Oven: Place in a covered baking dish at 350°F for 20-25 minutes, stirring halfway through.
The Golden Secret That Changes Everything
Here's what took me years to learn: the real magic happens when you save some of that caramelized onion butter from your skillet. After removing the onions, that golden, flavor-packed fat left in the pan is liquid gold. Drizzle it over your finished mashed potatoes just before serving.
This simple trick adds an extra layer of sweet, savory flavor that makes people wonder what your secret ingredient is. The butter carries all those concentrated caramelized bits and aromatics, creating a restaurant-quality finish. Another secret? Let your Caramelized Onion Mashed Potatoes Recipe rest for 5 minutes after mixing. This allows the flavors to marry and the texture to settle into that perfect creamy consistency. These two small steps separate good mashed potatoes from unforgettable ones.
FAQ
Can you put caramelized onions in mashed potatoes?
Absolutely! Caramelized onions are a perfect addition to mashed potatoes. The sweet, rich flavor of slow-cooked onions complements the creamy texture beautifully. Fold them in after mashing, or use them as a topping. This Caramelized Onion Mashed Potatoes Recipe proves they're a match made in comfort food heaven.
What does Gordon Ramsay put in his mashed potatoes?
Gordon Ramsay uses a generous amount of butter, heavy cream, and seasons with salt and white pepper. He also emphasizes using a ricer for ultra-smooth texture and heating the cream before adding it. His technique focuses on proper seasoning and incorporating fats while the potatoes are still hot for maximum absorption.
What is the trick to caramelizing onions?
The key is patience and medium-low heat. Use enough fat to coat the onions, add a pinch of salt to draw out moisture, and cook for 25-30 minutes, stirring every few minutes. Don't rush the process; true caramelization takes time. If they're browning too fast, lower the heat. A splash of water helps deglaze any stuck bits.
What is a common mistake when making mashed potatoes?
The biggest mistake is over-mixing, which activates too much starch and creates gummy, gluey potatoes. Stop mashing once the lumps are gone. Another error is adding cold cream or milk, which shocks the hot potatoes and prevents them from absorbing the liquid properly. Always use warm cream for this Caramelized Onion Mashed Potatoes Recipe.
Wrapping Up This Comfort Classic
This Caramelized Onion Mashed Potatoes Recipe deserves a permanent spot in your recipe collection. The combination of sweet caramelized onions and creamy, buttery potatoes creates a side dish that works for both everyday dinners and special occasions. Once you've mastered this recipe, you'll find yourself making it again and again.
The best part? It pairs beautifully with so many dishes. Serve it alongside a warming Carrot Cumin Soup Recipe for a cozy vegetarian meal, or pair it with Miso Noodle Soup Recipe for an unexpected fusion dinner. These caramelized onion mashed potatoes are versatile enough to complement almost anything on your table. Try this Caramelized Onion Mashed Potatoes Recipe this week, and don't forget to share your results in the comments below!
With love-By Lisa Johnson 🍴💛
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Caramelized Onion Mashed Potatoes Recipe
Equipment
- 1 Large Heavy-Bottomed Pot Even cooking for potatoes
- 1 Cast-iron or stainless steel skillet Best for caramelizing onions
- 1 Potato masher Creates creamy yet textured mash
- 1 Fine-mesh strainer or colander Drains potatoes thoroughly
- 1 Wooden spoon Gentle stirring without scratching
- 1 Small saucepan To warm cream and butter mixture
Ingredients
Mashed Potatoes
- 3 pounds Yukon Gold potatoes Creamiest texture, holds shape well
- 1 cup Heavy cream Adds richness and silkiness
- 6 tablespoons Butter Unsalted preferred for flavor control
- Salt and black pepper To taste
- 2 cloves Garlic, minced Optional, adds depth
Caramelized Onions
- 3 large Yellow onions, thinly sliced Caramelizes beautifully
- 3 tablespoons Butter For caramelizing onions
- 1 tablespoon Olive oil Prevents butter from burning
- 1 teaspoon Sugar Optional, speeds caramelization
- 2 tablespoons Fresh thyme leaves Adds earthy aroma
- Salt To taste for onions
Instructions
- Heat skillet with butter and olive oil; add onions, salt, and sugar. Cook slowly until golden brown (25–30 min), stir occasionally, add thyme near end.
- Peel and chop potatoes; boil in salted water until fork-tender (15–18 min). Drain and steam dry.
- Warm cream, butter, and garlic in saucepan. Mash potatoes, gradually add cream mix, fold in most onions.
- Taste, adjust seasoning, top with reserved onions and butter pat. Serve hot with thyme garnish.
Notes
- Nutrition information is automatically calculated, so should only be used as an approximation.













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