Twice Baked French Onion Mashed Potatoes
Twice Baked French Onion Mashed Potatoes with caramelized onions and Gruyère cheese are a delicious side dish that just might be more popular than the main meal!
Servings: 8 people
Calories: 424kcal
Ingredients
Caramelized Onions
- 3 large yellow onions (about 2 pounds total), sliced into half moons
- 2 tablespoons extra virgin olive oil
- 1 tablespoon unsalted butter
- ½ teaspoon kosher salt
- 1-2 tablespoons water or broth, for deglazing
Potatoes
- 3 pounds red potatoes, washed, peeled, quartered
- ½ cup (1 stick / 113 g) unsalted butter
- ½ cup (119 g) heavy whipping cream
- 1 teaspoon kosher salt
- ½ teaspoon black pepper
- 1 cup (113 g) Gruyere cheese, shredded, divided
- parsley, chopped for garnish
Instructions
Caramelized Onions
- To a large skillet over medium heat, add the olive oil and butter. Once the oil is shimmering and the butter is melted, stir to combine.
- Add the sliced onions and toss them to coat evenly. Spread them out into an even layer across the skillet.
- Sprinkle the kosher salt over the onions. This helps draw out moisture, which is essential for even caramelization.
- Reduce heat to medium-low. Let the onions cook, stirring them every 5–10 minutes. You want to allow them time to rest against the pan so they brown slowly and evenly.
- Continue cooking, stirring occasionally, for 60-70 minutes total. The onions should turn a deep golden brown, become very soft, and almost jammy in texture. (If at any point the onions look like they’re browning too fast or burning on the bottom, reduce the heat slightly and add a splash of water or broth to deglaze and scrape up any browned bits.)
Potatoes
- While the onions are cooking, place the potatoes in a large pot and cover them with cold water.
- Set the pot over high heat and cover with a lid. Let the water come to a full boil.
- Once boiling, remove the lid and reduce the heat to medium-high. Simmer the potatoes until they’re fork-tender, about 20–25 minutes.
- While the potatoes are boiling, preheat the oven to 425°F (220°C). Lightly grease a 10-inch oven-safe skillet* and set aside.
- Drain the cooked potatoes and return them to the pot. Use a potato masher to mash lightly.
- Add the butter, heavy whipping cream, salt, black pepper, and half of the shredded Gruyère cheese. Continue mashing and stirring until the mixture is smooth and creamy.
- Spoon the mashed potatoes into the prepared baking dish, spreading them out evenly.
- Sprinkle the remaining Gruyère cheese evenly over the top.
- Bake for 15–20 minutes, or until the cheese is fully melted and golden brown on top.
- Remove from the oven. Top with the warm caramelized onions.
- Garnish with chopped parsley and serve warm.
Notes
*If you don’t have a 10-inch oven-safe skillet, you can bake these potatoes in an 8x8-inch or 9x9-inch square dish. (The recipe makes about 6 cups of mashed potatoes.) A 2.5-quart round casserole dish or a 7x11-inch rectangular baking dish would also work.
Nutrition
Serving: 1portion | Calories: 424kcal