Food & Cooking Recipes Healthy Recipes Gluten-Free Recipes Mashed Potatoes and Celeriac with Wild Mushrooms 3.8 (5) Add your rating & review By Martha Stewart Test Kitchen Martha Stewart Test Kitchen The recipes developed by our test kitchen team have undergone a rigorous process of development and testing, ensuring that every element is optimal, from ingredient amounts to method and cooking time. This process includes triple-testing recipes to ensure they meet our high standards. The many stellar cooks and food editors who have been part of our team include Sarah Carey, Lucinda Scala Quinn, Jennifer Aaronson, Shira Bocar, Anna Kovel, Greg Lofts, Riley Wofford, Lauren Tyrell, and Lindsay Leopold. Editorial Guidelines Updated on June 12, 2017 Print Rate It Share Share Tweet Pin Email Servings: 10 Wild mushrooms sauteed in sherry make a rich topping for Thanksgiving mashed potatoes, and roasted celeriac lends the dish a slightly nutty flavor. Ingredients 7 medium Yukon Gold, or Idaho potatoes (about 3 ½ pounds) 2 tablespoons salt 2 medium heads celeriac (about 1 pound each), peeled and cut into ½-inch dice 2 tablespoons olive oil 3 tablespoons Homemade Chicken Stock, or low-sodium canned chicken broth, skimmed of fat ¾ teaspoon freshly ground black pepper ½ cup heavy cream 1 cup milk 6 tablespoons unsalted butter 1 pound assorted wild mushrooms, trimmed and cut into ¾-inch pieces 4 ½ teaspoons chopped fresh rosemary ¼ cup dry sherry 4 teaspoons snipped chives Directions Heat oven to 425 degrees. Place potatoes in a medium stockpot, cover with water, and add 1 tablespoon salt; bring to a boil. Reduce heat to medium high, and boil gently until potatoes are tender, about 45 minutes. Drain potatoes in a colander. When cool enough to handle, peel potatoes, and pass the flesh through a potato ricer into a large metal bowl. Cover with aluminum foil, and place over a pot of simmering water. Meanwhile, in a medium bowl, combine celeriac, 1 tablespoon olive oil, 1 tablespoon chicken stock, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Transfer to a shallow baking pan, and roast until celeriac is browned and tender, about 35 minutes. Remove from oven, and stir celeriac into potatoes. Cover bowl of potatoes again. In a small saucepan, combine cream, milk, and 4 tablespoons butter; warm over medium-high heat until butter melts and milk just comes to a boil, about 2 minutes. Stir into the potato and celeriac mixture along with 2 tablespoons salt and 1/4 teaspoon pepper. Cover bowl again. In a large skillet, heat remaining tablespoon olive oil and remaining 2 tablespoons butter over medium-high heat. Add the sturdiest mushrooms to skillet. Saute, stirring frequently, until mushrooms are lightly browned, 2 to 3 minutes. Add remaining mushrooms, 3 teaspoons rosemary, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Cook until mushrooms are tender, 3 to 5 minutes. Add sherry and remaining 2 tablespoons stock, and cook until mushrooms absorb the liquid, 2 to 3 minutes. Transfer potatoes and celeriac to a serving dish and cover with mushrooms. Sprinkle with the remaining 1 1/2 teaspoons rosemary, and serve immediately. Cook's Notes The celeriac, or celery root, can be roasted ahead of time; let it stand at room temperature until you're ready to add it to the mashed potatoes. Rate it Print