Potato and Shiitake Mushroom Gratin

Step 1

Melt butter or margarine in a large pot over high heat. Add all mushrooms, and saute; until liquid evaporates, about 10 minutes.

Step 2

Add garlic, thyme, and rosemary; saute; 1 minute.

Step 3

Add chicken broth. Simmer until liquid evaporates, stirring often, about 18 minutes.

Step 4

Season with salt and pepper. Cool.

Step 5

Position 1 rack in middle of the oven, and another rack in bottom third of oven. Preheat to 375 degrees F (190 degrees C).

Step 6

Butter a 13x9x2 inch baking dish.

Step 7

Peel potatoes, and cut into 1/8 inch slices.

Step 8

Arrange 1/3 of the potatoes in prepared dish, overlapping slightly.

Step 9

Top potatoes with half of the mushroom mixture.

Step 10

Sprinkle 1/3 of the cheese over mushrooms.

Step 11

Repeat layering 1/3 of the potatoes, remaining mushroom mixture, and 1/3 of the cheese.

Step 12

Arrange remaining potatoes atop cheese.

Step 13

Whisk half and half, cream, 1 1/4 teaspoon salt, and 1 teaspoon pepper in a large bowl to blend. Pour mixture over potatoes.

Step 14

Cover loosely with foil.

Step 15

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,.

Step 16

Uncover, using metal spatula, press on potatoes to submerge.

Step 17

Sprinkle remaining cheese over potatoes.

Step 18

Bake until cheese melts and gratin is golden at edges, about 15 minutes longer. Let stand 10 minutes.