This gratin combines two comforting ingredients to their mutual advantage --and ours. Sliced potatoes encircle a casserole dish, with assorted wild mushrooms, such as chanterelle and oyster, taking spots alongside more potatoes. Fresh thyme gives the pie herbal undertones; Gruyere and Parmesan, melting in and around the layers during baking, make it soul-satisfying.

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Ingredients

Ingredient Checklist

Directions

Instructions Checklist
  • Preheat oven to 350 degrees. Butter a 13-by-9-inch baking dish; set aside. Melt butter in a large skillet over medium heat. Add onion; cook, stirring occasionally, until softened, about 5 minutes. Add half of the mushrooms; cook until they are slightly softened. Add remaining mushrooms; cook, stirring occasionally, until mushrooms have released their juices and most of the liquid has evaporated, 8 to 10 minutes. Add wine; cook, stirring occasionally, until liquid has evaporated, 3 to 5 minutes. Remove from heat. Season with salt and pepper.

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  • Combine cheeses in a small bowl; set aside. Cover bottom of prepared dish with potato slices, slightly overlapping them. Sprinkle with half of the thyme and a pinch each of salt and pepper. Sprinkle with 1/3 of the cheese and half of the mushroom mixture. Repeat layering process, using all but 2 tablespoons cheese. Arrange remaining potato slices, slightly overlapping, around the edge of the dish. Stir together milk and cream in a bowl, and pour over top. At this point, dish can be refrigerated, covered, up to 1 day; let stand at room temperature 30 minutes before baking.

  • Cover loosely with foil, and bake until bubbling, about 1 hour. Remove foil, and sprinkle with reserved cheese. Bake until top is golden, 20 to 30 minutes more. Transfer dish to a wire rack; let cool 10 minutes before serving.

Cook's Notes

Use a mandoline to make thin, even potato slices.

Reviews (14)

214 Ratings
  • 5 star values: 33
  • 4 star values: 38
  • 3 star values: 82
  • 2 star values: 54
  • 1 star values: 7
Rating: Unrated
03/02/2016
it tasted good but the sauce separated and looked curdled I wouln't want to serve it a party like this, anyone know where I went wrong? maybe the mushrooms weren't dry enough?
Rating: Unrated
12/17/2013
Question: I am hoping to take this to a Christmas party. Can I cook it at home for the hour, and then the rest of the 30min to golden the cheese after I arrive at my holiday location (about 2hrs later)?
Rating: Unrated
11/14/2011
Jidiji - I've made this two or three times, and yes, it does take the full time stated to cook. I was also sceptical about the cooking time before I'd tried it, seeing as the mandoline slices the potato so thinly, however, it really wasn't done until it had the full time. It's absolutely decicious!
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Rating: Unrated
11/20/2008
Do you have to use Yukon Gold potatoes? Would Russet work just as well?
Rating: Unrated
11/14/2008
Does this recipe REALLY take 1 1/2 hrs. total to bake???? If you're slicing the potatoes on a mandoline, what is it exactly that takes 1 1/2 to cook?
Rating: Unrated
11/13/2008
alibee, a mandoline is a slicer that is usually used on an angle. It is very sharp and helps to assist in getting more uniform slices versus you slicing by hand. You can find them at BB
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Rating: Unrated
11/13/2008
What's a mandoline?
Rating: Unrated
06/26/2008
This is so delicious ! If the grocery doesn't have exact mushrooms I make it with Portabellos and it's very good. It looks special and your family and friends will love the extra mile you went.
Rating: Unrated
12/03/2007
You're right, the Gruyere cheese was accidentally omitted from the ingredients list. The error has been fixed. Thank you!
Rating: Unrated
11/21/2007
Potato-Mushroom Pie: I have the original recipe from Martha Stewart Living magazine and it calls for "1 cup finely grated Gruyere cheese (about 4 ounces)". Everything else is the same. I think they just left this out by mistake.
Rating: Unrated
11/18/2007
I have the same question about the cheeses. Also, I am taking this dish to my son's Thanksgiving dinner. Because of oven space, can I bake this at home and reheat it just before dinner is served? Please respond ASAP. Many thanks.
Rating: Unrated
11/16/2007
I'd also be interested in tring to make this for Thanksgiving dinner, I always wanted an option other than mashed and this one does not seem too difficult. Just wondering what other cheeses would work and is there another cheese that is left out of the origional recipe?
Rating: Unrated
11/16/2007
I second that request! I would like to fix this with my Christmas dinner and need to have that answered as well. Someone at Martha's: PLEASE ANSWER THIS!
Rating: Unrated
11/14/2007
The ingredients call for only parmesan cheese but the instructions direct to "combine cheeses." I certainly don't want to miss out on any cheese and plan to make this for Thanksgiving this year. Any direction would be appreciated