POTATO AND SHIITAKE MUSHROOM GRATIN

Steps:

• Melt butter or margarine in a large pot over high heat. Add all mushrooms, and saute; until liquid evaporates, about 10 minutes.
• Add garlic, thyme, and rosemary; saute; 1 minute.
• Add chicken broth. Simmer until liquid evaporates, stirring often, about 18 minutes.
• Season with salt and pepper. Cool.
• Position 1 rack in middle of the oven, and another rack in bottom third of oven. Preheat to 375 degrees F (190 degrees C).
• Butter a 13x9x2 inch baking dish.
• Peel potatoes, and cut into 1/8 inch slices.
• Arrange 1/3 of the potatoes in prepared dish, overlapping slightly.
• Top potatoes with half of the mushroom mixture.
• Sprinkle 1/3 of the cheese over mushrooms.
• Repeat layering 1/3 of the potatoes, remaining mushroom mixture, and 1/3 of the cheese.
• Arrange remaining potatoes atop cheese.
• Whisk half and half, cream, 1 1/4 teaspoon salt, and 1 teaspoon pepper in a large bowl to blend. Pour mixture over potatoes.
• Cover loosely with foil.
• Place baking dish on middle rack in oven, and a baking sheet on the bottom rack. Bake until potatoes are tender and liquid thickens, about 1 hour and 15 minutes,.
• Uncover, using metal spatula, press on potatoes to submerge.
• Sprinkle remaining cheese over potatoes.
• Bake until cheese melts and gratin is golden at edges, about 15 minutes longer. Let stand 10 minutes.