Potato, Leek, Gruyere, Oyster Mushroom Gratin

Serves 10

Ingredients:

• 4 tablespoons (½ stick) butter
• 1 pound oyster mushrooms, halved if large
• 1 tablespoon minced garlic
• 4 cups thinly sliced leeks (white and pale green parts only; about 4 large)
• 1 tablespoon minced fresh thyme
• 1 ¾ cups canned low-salt chicken broth
• 1 ¾ cups whipping cream
• ¼ cup dry white wine
• 1 teaspoon salt
• ½ teaspoon ground black pepper
• 3 ¾ pounds russet potatoes, peeled, thinly sliced into rounds (about 8 cups)
• 2 ½ cups grated Gruyère cheese (about 10 ounces) Guoda works well too.

Directions:

1. Melt 2 tablespoons butter in heavy large skillet over medium-high heat.
2. Add mushrooms and sauté until almost tender, about 5 minutes.
3. Add garlic and sauté until mushrooms are tender and golden, about 3 minutes longer.
4. Transfer mushroom mixture to bowl. Melt remaining 2 tablespoons butter in same skillet over medium high heat.
5. Add leeks and thyme and sauté until leeks are tender and beginning to brown, about 8 minutes.
6. Add leek mixture to bowl with mushrooms.
7. Preheat oven to 400˚F.
8. Butter 13 x 9 x 2-inch baking dish. Whisk broth, cream, wine, 1 teaspoon salt and ½ teaspoon pepper in large bowl to blend.
9. Layer ⅓ of potatoes on bottom of prepared dish.
10. Top with half of mushroom-leek mixture, then ¾ cup cheese. Top with half of remaining potatoes. Pour half of cream mixture over.
11. Top with remaining mushroom-leek mixture and ¾ cup cheese.
12. Cover with remaining potatoes. Pour remaining cream mixture over; sprinkle with remaining cheese.
13. Bake gratin uncovered until potatoes are tender and sauce bubbles thickly, about 1 hour 20 minutes.
14. Let gratin stand 30 minutes before serving.