These Caramelized Onion Mashed Potatoes transform a classic comfort dish into something extraordinary, blending creamy texture with rich, sweet onion flavor.
Naturally gluten-free and packed with fiber, this recipe offers healthy fats from olive oil and optional dairy-free milk.
Quick to prepare yet deeply satisfying, it’s a perfect choice for weeknight dinners, holiday feasts, or meal prep.
Caramelized Onion Mashed Potatoes
Equipment
- 1-Large skillet
- 1-Large pot
- 1 knife
- 1 cutting board
- 1 Potato Masher
- 1 measuring cup
- 1 Measuring spoon
- Mixing bowl
Ingredients
Mashed Potatoes:
- 2 tbsp olive oil
- 4 yellow onions thinly sliced
- 2 lb Yukon Gold potatoes washed and chopped
- 4 tbsp salted butter or non-dairy butter
- ¾ cup half & half or full-fat coconut milk or dairy-free milk
- 1 tsp kosher salt
- 1 cup freshly grated Parmesan cheese
Topping:
- 1 bunch chives thinly chopped
- 2 sprigs fresh thyme stems removed
- 3 fresh sage leaves chopped
Instructions
- Prepare and Slice Onions: Start by peeling the yellow onions carefully. Trim off both ends, then slice each onion evenly and thinly to ensure they cook uniformly. Aim for slices about 1/8 inch thick — not too thin that they disintegrate, and not too thick so they stay crunchy. Having evenly sliced onions ensures smooth caramelization later. Set these aside in a clean bowl until ready.
- Caramelize the Onions Slowly: Place a large skillet or frying pan over medium heat. Add 2 tablespoons of olive oil and allow it to warm until it shimmers slightly. Add the sliced onions to the skillet in an even layer. Stir occasionally to prevent burning, letting them soften slowly. This process should take about 40 to 50 minutes. The onions will first turn translucent, then gradually develop a deep golden-brown color with a sweet, rich aroma. Patience is key — low and slow cooking will ensure maximum flavor and natural sweetness. Once caramelized, remove half of the onions from the skillet and set aside for later use as a topping. Keep the other half in the pan to mix into the mashed potatoes.
- Wash and Chop Potatoes: While the onions cook, wash the Yukon Gold potatoes thoroughly under running water to remove dirt and impurities. Optionally peel the potatoes if you prefer a smoother texture, though leaving the skin adds extra fiber, texture, and nutrients. Chop the potatoes into evenly sized chunks, about 1 to 2 inches, so they cook evenly. Place the chopped potatoes in a large bowl until ready to cook.
- Boil the Potatoes: Fill a large pot with enough water to fully submerge the potato chunks. Place the pot on the stove over high heat and bring the water to a rolling boil. Add a pinch of salt to season the water. Carefully add the chopped potatoes to the boiling water. Let them cook for about 20 minutes or until they are fork-tender — meaning a fork slides easily through the pieces without resistance. Avoid overcooking to prevent them from becoming waterlogged.
- Drain and Mash Potatoes: Once the potatoes are cooked, drain them thoroughly in a colander to remove all excess water. Return the potatoes to the pot or place them in a large mixing bowl. Using a potato masher (or a ricer if desired), mash the potatoes until they are smooth and free of lumps.
- Add Cream and Butter: To make the mashed potatoes rich and creamy, add 4 tablespoons of salted butter (or non-dairy butter) directly to the hot potatoes so it melts completely. Pour in ¾ cup of half & half (or full-fat coconut milk/dairy-free milk for a vegan option). Sprinkle in 1 teaspoon of kosher salt. Stir and mash again until the mixture is smooth and creamy, with a luscious, velvety texture. Adjust consistency with extra milk if desired.
- Fold in Caramelized Onions and Parmesan: Add half of the caramelized onions from Step 2 into the mashed potatoes. Then add 1 cup of freshly grated Parmesan cheese. Using a spatula or masher, gently fold these ingredients into the potatoes until well blended. This step ensures that the mashed potatoes absorb the sweet, savory flavor of the onions and the richness of the Parmesan cheese. Taste and adjust seasoning if needed.
- Plate and Add Toppings: Transfer the mashed potatoes into a large serving bowl. Evenly scatter the remaining caramelized onions over the top. Sprinkle generously with thinly chopped fresh chives, chopped thyme leaves, and chopped sage for a fragrant, herbaceous finish. Drizzle with a small amount of melted butter for extra richness.
- Serve and Enjoy: Serve your caramelized onion mashed potatoes immediately while warm. They make a delightful side dish for Thanksgiving dinners, holiday feasts, cozy family meals, or even as a hearty comfort-food option any day of the week. These mashed potatoes pair wonderfully with roasted meats, baked chicken, or vegetarian main courses.
Notes
- For best flavor, slice onions evenly so they caramelize at the same rate.
- Yukon Gold potatoes are ideal for their creamy texture, but russets can work if desired.
- Leaving potato skins on adds fiber and nutrients while creating a rustic texture.
- Use low heat for onions to avoid burning and to develop maximum sweetness.
- Fresh herbs like chives, thyme, and sage elevate flavor, but dried herbs work in a pinch.
- Adjust milk or butter amounts for your preferred creaminess.
- Parmesan cheese can be substituted with nutritional yeast for a dairy-free option.
Chef’s Secrets For Ultimate Flavor
The magic of this mashed potato recipe lies in the slow caramelization of onions.
This process transforms the onions into deeply sweet, savory gems that infuse the potatoes with irresistible flavor.
A gentle, patient cooking approach over low to medium heat unlocks the best results.
Fresh herbs, especially thyme and sage, complement the richness of the potatoes while adding an aromatic lift.
For extra creaminess, blend the mashed potatoes with a hand mixer instead of mashing by hand.
Lastly, always taste and season toward the end to ensure balanced flavor.
Serving Suggestions For Perfect Meals
These caramelized onion mashed potatoes pair beautifully with roasted meats like turkey, chicken, beef, or pork, making them ideal for holiday feasts.
They also work as a standout side for vegetarian dishes, such as mushroom Wellington, grilled portobello, or lentil loaf.
For an elegant touch, serve in a shallow bowl topped with extra caramelized onions and a sprinkle of fresh herbs.
They’re equally comforting as a standalone dish for a cozy dinner.
Pair them with a light salad or roasted vegetables for a complete, balanced meal.
Storage Tips For Freshness
Store leftover mashed potatoes in an airtight container in the refrigerator for up to three days.
To keep the potatoes creamy when reheating, add a splash of milk or plant-based milk, then stir gently while warming on the stovetop or in the microwave.
Caramelized onions store beautifully in a separate container in the fridge for up to five days and can be reheated lightly before serving.
For longer storage, freeze mashed potatoes in airtight containers for up to two months, thawing overnight before reheating.
Frequently Asked Questions
1. Can I make caramelized onion mashed potatoes ahead of time?
Yes! You can prepare the mashed potatoes and onions in advance. Store them separately in airtight containers. Reheat gently and combine before serving for the best texture and flavor.
2. Can I use russet potatoes instead of Yukon Gold?
Absolutely. Russet potatoes work well and create a light, fluffy texture. Yukon Gold offers a creamier consistency, so choose based on your texture preference.
3. How can I make this recipe dairy-free?
Replace butter with plant-based butter and use full-fat coconut milk or another dairy-free milk. Nutritional yeast can replace Parmesan cheese for a similar savory taste.
4. How do I know when onions are perfectly caramelized?
Caramelized onions should be soft, golden to deep brown, and sweet-smelling. They should not be burnt — a slow cook over low heat for 40–50 minutes usually ensures perfect caramelization.
5. Can I add extra flavor to mashed potatoes?
Yes! Garlic, roasted herbs, or a touch of truffle oil can add depth. You can also experiment with cheeses like gruyere or asiago for a unique flavor profile.
