French Onion Mashed Potatoes

Mashed potatoes topped with caramelized onions and fresh thyme.

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French Onion Mashed Potatoes

These French onion mashed potatoes take the classic soup recipe and combine it with rich creamy mashed potatoes for an unbelievable side dish. Rich, caramelized onions stirred into buttery potatoes with plenty of gruyere cheese and more.

Prep Time30

Cook Time1

Total Time1 30

Course: Side Dish

Cuisine: American

Servings:

Author: Lorie Yarro

Ingredients

Caramelized Onions

3 medium sweet onions sliced
2 Tbsp butter
1 Tbsp olive oil
Pinch of sea salt
0ptional splash of balsamic vinegar

Mashed Potatoes

4 lb Yukon gold potatoes skin on or off, cut into 2-inch pieces, or a combo of russet and Yukon gold
optional: 1-2 cups beef broth added to the water
½ tsp sea salt
2-3 garlic cloves minced
6-8 Tbsp salted butter melted
1 cup shredded gruyere cheese
1 - 1¼ cup heavy cream room temperature or slightly warmed
¼ - ⅓ cup sour cream room temperature
½ tsp pepper
1-2 tsp fresh thyme more to garnish
sea salt to finish as desired

Instructions

Make the Onions: Heat the butter and oil in a 10-12-inch large skillet over medium heat. Add the onions and sauté for 7-10 minutes, or until starting to soften.
Reduce the heat to medium-low and cook for about 50 minutes to 1 hour, stirring every few minutes, or until the onions are golden brown, and caramelized. Timing can vary, so allow for an extra 10-20 minutes even, or shift heat a touch higher to speed things up. When onions are caramelized, add sea salt and a splash of balsamic vinegar if desired and stir to mix in.
Start the Potatoes: When the onions are about 25 minutes into cooking, add cut, 2-inch pieces of potatoes to a large pot. Don't cut them too small. You can peel the potatoes or leave the skin on. Add beef broth if using and then cold water to cover the potatoes by about an inch.
Add salt and minced garlic to the pot. Bring the water to a boil at medium-high heat. Once boiling, reduce to medium heat and gently boil for about 15 minutes or until the potatoes are fork tender (you can easily poke a fork through the potato).
Drain the potatoes and return to the pot, allowing the potatoes to sit on the hot burner for a minute or so to dry out more.
Once the potatoes are drained and dried out of excess water, use a potato masher to start mashing the potatoes. Add the butter, about half of the cream, gruyere cheese, pepper, thyme and sour cream and continue mashing until blended, cheese is melted and the potatoes are desired consistency. You can add more cream as desired.
Gently fold in about ⅔ of the caramelized onions. Transfer to a serving dish and add remaining onions over top before serving. Sprinkle with more thyme to garnish if desired.

Notes

Storage: Allow the potatoes to completely before sealing in an airtight container. Store in the refrigerator for about 3-4 days. Caramelized potatoes freeze quite well, so you can alternatively freeze the potatoes for up to 3 months. Thaw overnight before reheating.

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