Go Back

Caramelized Onion Mashed Potatoes

Caramelized onion mashed potatoes combine Yukon Gold potatoes mashed with warm milk and butter with deeply golden, soft onions. The onions cook slowly in a skillet before being folded into the creamy potatoes for a rich, savory side dish.
Print Recipe Pin Recipe
Prep Time 15 minutes
Cook Time 1 hour 8 minutes
Total Time 1 hour 23 minutes
Servings: 6 servings
Course: Side Dish
Cuisine: American
Calories: 430
Ingredients Equipment Method Notes

Ingredients
  

For the onions
  • 1 tbsp olive oil
  • 2 tbsp unsalted butter for the onions
  • 2 yellow onions large (about 1 1/2 pounds), thinly sliced
  • 0.5 tsp kosher salt for the onions
  • 0.33 cup water for the onions
For the potatoes
  • 6 tbsp unsalted butter for the potatoes
  • 1 tbsp kosher salt for the potato water
  • 3 qt water for the potatoes
  • 3 lb Yukon Gold potatoes peeled and cut into 1 1/2-inch chunks
  • 0.75 cup whole milk
  • 0.25 tsp black pepper

Equipment

  • 1 12-inch skillet
  • 1 microwave

Method
 

Caramelize the onions
  1. Heat the olive oil and 2 tablespoons of the butter in a 12-inch skillet over medium-low heat until the butter melts.
  2. Add the onions and 1/2 teaspoon of the salt and cook for 35 to 45 minutes, stirring every few minutes, until deeply golden and very soft; lower the heat if they brown too quickly.
  3. Add 1/3 cup of the water and scrape up the browned bits.
  4. Cook until the water evaporates.
Boil and mash the potatoes
  1. Put the potatoes in a 6-quart pot with 3 quarts cold water and the remaining 1 tablespoon salt.
  2. Bring to a boil over high heat, then reduce the heat and simmer for 15 to 20 minutes, until the potatoes are fork-tender.
  3. Drain the potatoes and return them to the hot pot; let them steam for 1 to 2 minutes.
  4. Warm the milk in a microwave-safe measuring cup for 30 to 45 seconds, until hot but not boiling.
  5. Add the warm milk and remaining 6 tablespoons butter to the potatoes and mash just until creamy.
  6. Fold in the caramelized onions and black pepper.

Notes

For the softest texture, mash the potatoes just until creamy. Refrigerate leftovers for up to 4 days; freezing is not recommended because the potatoes may become grainy. For a dairy-free variation, use unsweetened dairy-free milk and a dairy-free butter alternative.