ArrowDownFill 1arrow-small-lineFill 1Cooking Light - EasyCooking Light - FastCooking Light - So GoodCooking Light - How-ToCooking Light - Staff FaveCooking Light Badge - Wow!GroupClose IconEmailEmpty Star IconLike Cooking Light on FacebookFull Star IconShapePage 1 Copy 3Page 1 Copy 2Grid IconHalf Star IconFollow Cooking Light on InstagramList IconMenu IconPrintSearch IconSpeech BubbleFollow Cooking Light on SnapchatFollow Cooking Light on TwitterWatch Cooking Light on YouTubeplay-iconWatch Cooking Light on Youtube

Potato, Leek, and Mushroom Gratin

Yield Makes 10 to 12 servings
Notes: Using a mandoline to slice the potatoes makes a quick job of it. You can make this gratin up to 1 day ahead; bake it covered, let it cool, then chill. The next day, let gratin stand at room temperature for about 1 hour, then bake, uncovered, in a 350° oven until hot in the center, about 1 hour. If it starts to get too brown, cover loosely with foil. Prep and Cook Time: about 2 1/2 hours.

Ingredients

  • 1/4 cup (1/8 lb.) butter
  • 1 pound fresh shiitake mushrooms, rinsed, stems removed, and sliced
  • 1 tablespoon minced garlic
  • 4 leeks (3 1/2 lb. total)
  • 1 tablespoon minced fresh thyme leaves
  • 3 3/4 pounds russet potatoes
  • 1 3/4 cups low-sodium chicken broth
  • 1 3/4 cups whipping cream
  • 1/4 cup dry white wine
  • 1 teaspoon salt
  • 1/2 teaspoon pepper
  • 3 1/2 cups shredded Gruyère cheese (12 oz.)

Nutrition Information

  • calories 408
  • caloriesfromfat 55 %
  • protein 14 g
  • fat 25 g
  • satfat 15 g
  • carbohydrate 35 g
  • fiber 2.8 g
  • sodium 379 mg
  • cholesterol 82 mg

How to Make It

  1. In a 12-inch frying pan or 5- to 6-quart pan over medium-high heat, melt 2 tablespoons of the butter. Add mushrooms and stir often until almost tender, 4 to 5 minutes. Add garlic and stir until mushrooms are golden and tender to bite, 2 to 3 minutes longer. Transfer to a bowl.

  2. Trim and discard root ends and tough green tops from leeks. Cut stalks in half lengthwise and rinse well under running water, flipping layers to release dirt. Cut crosswise into 1/4-inch slices; you should have about 4 cups.

  3. In the frying pan (no need to wash), over medium-high heat, melt remaining 2 tablespoons butter. Add leeks and thyme and stir often until leeks are limp and beginning to brown, 8 to 10 minutes. Stir into mushrooms.

  4. Preheat oven to 350°. Peel and slice potatoes crosswise as thinly as possible (see notes). In a bowl, whisk together broth, cream, wine, salt, and pepper. In a buttered 9- by 13-inch baking dish (3-qt. capacity), evenly layer a third of the potatoes, half of the mushroom-leek mixture, and 1 cup cheese. Stir broth-cream mixture and pour a third evenly over the top. Repeat. Layer remaining potatoes, cheese, then cream mixture on top. Set dish in a 10- by 15-inch baking pan.

  5. Bake until potatoes are tender when pierced and sauce is bubbly, 1 1/2 to 1 3/4 hours. After about 40 minutes, check browning; if top begins to get dark before potatoes are tender, cover loosely with foil. Let stand about 15 minutes before serving.