Layered Mashed Potato and Mushroom Casserole
- Active Time 1h 20m
- Total Time 2h
12 servings, about 3/4 cup each
Fancy up regular mashed potatoes with a layer of mushroom duxelle — a saute of finely chopped mushrooms and shallots. We omitted the traditional butter in the duxelle and added chard for a nutritional boost. Serve this hearty side in place of mashed potatoes at any holiday feast or enjoy it as a vegetarian main dish.
- 3 1/2 pounds potatoes, preferably Yukon Gold, peeled and cut into 1-inch pieces
- 1 1/2 pounds cremini or white mushrooms, halved
- 1 tablespoon butter
- 1/2 cup nonfat buttermilk
- 1 large egg plus 1 large egg white, beaten
- 1 1/4 teaspoons salt, divided
- 1 tablespoon extra-virgin olive oil
- 3/4 cup chopped shallots
- 3 cloves garlic, finely chopped
- 4 cups trimmed and finely chopped chard or spinach
- 1 cup mushroom broth or reduced-sodium beef broth
- 2 tablespoons all-purpose flour
- 1/2 teaspoon freshly ground pepper
- 1/2 teaspoon chopped fresh rosemary
- 1 cup freshly grated Parmesan cheese, divided
Bring 1 inch of water to a simmer in a large pot. Place the potatoes in a steamer basket, cover and steam over medium-low heat, replenishing the water as necessary, until the potatoes are fall-apart tender, 20 to 30 minutes.
Meanwhile, working in two batches, place the mushrooms in a food processor and pulse, stopping to scrape down the sides as needed, until the mushrooms are coarsely chopped.
Transfer the potatoes to a large bowl. Add the butter and mash until chunky-smooth. Gradually stir in the buttermilk, egg and egg white and 1 teaspoon salt. Set aside.
Heat the oil in a large skillet over medium heat. Add the shallots and garlic and cook, stirring, until fragrant and beginning to soften, about 1 minute. Add the mushrooms and cook, stirring often, until they release their liquid and the pan is almost dry, 10 to 12 minutes. Add the chard (or spinach) and continue to cook, stirring, until wilted, about 4 minutes. Whisk the broth and flour in a small bowl. Add to the pan along with the remaining 1/4 teaspoon salt, pepper and rosemary. Cook, stirring, until the mixture bubbles and thickens, about 1 minute.
Preheat oven to 400 degrees F.
To assemble, spread 1/2 of the mashed potatoes in an even layer in a 9 x 13-inch (or similar 3-quart) baking dish. Sprinkle half the Parmesan over the potatoes. Spread the mushroom mixture on top and spread the remaining potatoes over the mushroom layer. Top with the remaining Parmesan.
Bake until hot throughout and the top is golden brown, about 35 minutes.
Tip: Make Ahead: Assemble through Step 6, cover and refrigerate for up to 1 day. Bake, uncovered, in a 400 degree F oven until hot, 50 minutes to 1 hour. To reheat, bake, covered, at 350 degrees F until hot, 40 to 50 minutes.
Recipe reprinted by permission of Publisher. All rights reserved.
nutrition information per serving
196 calories; 5g total fat; 2g total saturated fat; 26mg cholesterol; 438mg sodium; 32g carbohydrates; 3g fiber; 8g protein
These nutrition facts are calculated according to the ingredients listed in this recipe. Any substitutions will change these facts. Although we strive for accuracy, please note that food manufacturers occasionally change their food formulas, which could affect the calculations as shown.
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