Baking mashed potatoes makes serving them to a crowd much easier because they don’t have to be served immediately after mashing. The caramelized onions and cheese make this recipe a perfect side dish for neighborhood gatherings.

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Caramelized Onion-Mashed Potato Bake

Makes: 6 - 8 servings

Prep Time25

Total Time1

Ingredients

4 lb russet potatoes
3 tsp table salt, divided
1¼ cups warm buttermilk
½ cup warm milk
¼ cup melted butter
½ tsp freshly ground black pepper
1¼ cups freshly grated Gruyère cheese
1 cup chopped caramelized onions
2 Tbsps chopped fresh parsley

Instructions

Preheat oven to 350°F. Peel potatoes; cut into 2-inch pieces. Bring potatoes, 2 teaspoons salt, and water to cover to a boil in a large Dutch oven over medium-high heat; boil 20 minutes or until tender. Drain. Return potatoes to Dutch oven, reduce heat to low, and cook, stirring occasionally, 3 to 5 minutes or until potatoes are dry.
Mash potatoes with a potato masher to desired consistency. Stir in warm buttermilk, warm milk, melted butter, pepper, and remaining 1 teaspoon salt, stirring just until blended.
Stir in Gruyère cheese, caramelized onions, and parsley, and spoon mixture into a lightly greased 21⁄2-quart baking dish or 8 (10-ounce) ramekins. Bake at 350°F for 35 minutes.

Notes

Caramelizing onions cooks them to a rich brown color and an intensified sweetness. This process takes time to dissolve the strong sulfur compounds, so don’t try to rush it or you’ll end up with browned onions instead of richly flavored caramelized ones that are as sweet as sugar. To caramelize onions, cut the onions into thin slices. Heat 2 tablespoons olive oil or butter per onion in a large skillet over medium heat. Add the onions, and cook 25 to 30 minutes, stirring often, or until deep golden brown. Sweet onions take longer to caramelize than other varieties due to their higher moisture content.