Cheesy Potato, Leek & Mushroom Gratin

Directions

Melt 2 tablespoons butter (or 1 tablespoon olive oil, 1 tablespoon butter) in heavy large skillet over medium-high heat.

Stir in mushrooms and sauté until almost tender, 4 to 6 minutes.

Stir in garlic and sauté until mushrooms are tender and golden, about 3 minutes longer.

Transfer mushroom mixture to bowl.

Melt remaining 2 tablespoons butter (or half olive oil, half butter) in same skillet over medium-high heat.

Stir in leeks and thyme and sauté until leeks are tender and beginning to brown, 7 to 9 minutes.

Add leek mixture to bowl with mushrooms. (Can be made 1 day ahead. Cover and refrigerate.)

Preheat oven to 400°F.

Butter 13 x 9 x 2-inch baking dish .

Combine broth, cream, wine, 1 teaspoon salt and ½ teaspoon pepper in large bowl, whisk to blend.

Layer ⅓ of potatoes on bottom of prepared dish.

Top with half of mushroom-leek mixture, then ¾ cup cheese.

Top with half of remaining potatoes.

Pour half of cream mixture over.

Top with remaining mushroom-leek mixture and ¾ cup cheese.

Cover with remaining potatoes.

Pour remaining cream mixture over, sprinkle with remaining cheese.

Bake gratin uncovered until potatoes are tender and sauce bubbles thickly, about 1 hour 20 minutes.

Let gratin stand 30 minutes before serving.