Mashed Potato & Roots Casserole

Rutabaga and/or celeriac give this casserole a more nuanced flavor, but you could also use turnips or kohlrabi—or make it with all potatoes instead.

Mashed Potato & Roots Casserole
Active Time:
30 mins
Total Time:
2 hrs


  • 2 ½ pounds russet potatoes, cut into 1-inch chunks

  • 2 ½ pounds rutabaga and/or celeriac (celery root), peeled and cut into 1-inch chunks

  • 8 cloves garlic, peeled

  • 1 (8 ounce) package reduced-fat cream cheese, softened

  • 2 cups reduced-fat plain Greek yogurt

  • 1 ½ cups reduced-fat milk

  • 1 tablespoon chopped fresh thyme plus 2 teaspoons, divided

  • 1 teaspoon salt

  • ½ teaspoon ground pepper


  1. Place potatoes, rutabaga (and/or celeriac) and garlic in a large pot. Cover with water. Cover and bring to a boil over high heat. Adjust heat to maintain a lively simmer. Cook until the vegetables are tender, about 15 minutes.

  2. Meanwhile, preheat oven to 350°F. Coat a 9-by-13-inch baking dish with cooking spray.

  3. Drain the vegetables and return to the pot; mash with a potato masher. Add cream cheese, yogurt, milk, 1 tablespoon thyme, salt and pepper; mash until evenly incorporated. Scrape into the prepared baking dish. Sprinkle with the remaining 2 teaspoons thyme.

  4. Bake until golden brown on top, 1 to 1 1/4 hours. Let stand for 15 minutes before serving.


To make ahead: Prepare through Step 3 and refrigerate for up to 2 days. Let stand at room temperature while the oven preheats.

Nutrition Facts (per serving)

174 Calories
5g Fat
25g Carbs
8g Protein
Nutrition Facts
Servings Per Recipe 14
Serving Size 3/4 cup
Calories 174
% Daily Value *
Total Carbohydrate 25g 9%
Dietary Fiber 3g 11%
Total Sugars 7g
Protein 8g 16%
Total Fat 5g 6%
Saturated Fat 3g 15%
Cholesterol 9mg 3%
Vitamin A 197IU 4%
Sodium 272mg 12%

Nutrition information is calculated by a registered dietitian using an ingredient database but should be considered an estimate.

* Daily Values (DVs) are the recommended amounts of nutrients to consume each day. Percent Daily Value (%DV) found on nutrition labels tells you how much a serving of a particular food or recipe contributes to each of those total recommended amounts. Per the Food and Drug Administration (FDA), the daily value is based on a standard 2,000 calorie diet. Depending on your calorie needs or if you have a health condition, you may need more or less of particular nutrients. (For example, it’s recommended that people following a heart-healthy diet eat less sodium on a daily basis compared to those following a standard diet.)

(-) Information is not currently available for this nutrient. If you are following a special diet for medical reasons, be sure to consult with your primary care provider or a registered dietitian to better understand your personal nutrition needs.

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