Be forewarned - this is comfort food at its best. There's no claim here that this is "diet food." And, although we don't usually eat such luxurious dishes on a daily basis in my house, it's a great recipe to indulge in when company is coming over or for a lovely Sunday family dinner.
A mixture of thinly-sliced potatoes, slivered mushrooms, heavy cream, real butter and Parmesan cheese come together in this recipe to create an amazing gratin that is a splendid side dish to roasted chicken or grilled meat. You can go the "lighter" route, however, and serve alongside a beautiful, fresh side salad.
Years ago I read that soaking the potato slices in water prior to assembling a potato gratin makes a world of difference. So, I've always done so for this recipe. It removes a lot of the starch so that the potatoes aren't so "gummy" once baked.
Mushrooms contribute a fabulous earthy flavor to the dish. The flavor of the mushrooms and minced garlic in this recipe combines with the cream to create a scrumptious sauce that permeates the potatoes oh, so delicately.
You'll, basically, be slicing the potatoes and soaking them in water first. Then, after prepping the mushrooms and garlic, the cream will be gently heated (and infused with thyme and garlic). Everything will get layered in a casserole dish and baked to golden-bliss perfection.
About 10 - 12 baking potatoes, peeled and thinly sliced
6 - 8 button mushrooms, cleaned and thinly sliced
4 tablespoons butter, cut into small cubes (plus 1 tablespoon more for coating casserole dish)
4 garlic cloves, peeled and minced
1 cup heavy cream
2 - 3 springs fresh thyme
1/2 cup shredded Parmesan cheese
1 tablespoon chopped fresh parsley or chives (for garnish)
Soak potatoes in a large bowl of cold water for 30 - 60 minutes. Drain water and dry potatoes with a clean towel (I spread the potatoes out on the towel, roll it up and gently squeeze).
Gently heat the cream, thyme and garlic over low heat in a small saucepan (do this during the last few minutes of potatoes soaking). Do not boil. Once cream is heated, turn off heat. Allow thyme and garlic to steep in cream until ready to assemble the gratin.
Preheat oven to 375 degrees.
Butter the bottom and sides of a large baking dish (mine was a 10-inch round, but a 9 x 13 dish would work).
Lay down a layer of potatoes (about a third of the slices called for in the recipe) in the bottom of the dish (I do this in a "shingling" style). Top with a third of the mushroom slices.
Sprinkle on salt and pepper. Dot with a third of the butter pieces.
Sprinkle on a third of the cheese.
Remove thyme stems from cream and discard (it's perfectly okay if some of the leaves remain in the cream). Ladle on a third of the cream. Be sure that you get some of the minced garlic in each layer.
Continue this layering process until all of the ingredients have been used. (You'll be creating three layers total.)
Bake for an hour to an hour and a half. You're looking for the potatoes to be tender and for them to have absorbed the cream. Timing may vary here .. you may need a little more time depending on the thickness of your potatoes and layers. If your potatoes still need a little browning on top, raise oven temperature to 400 degrees toward the last 10 minutes or so of baking and continue baking until the top and sides are golden brown.
Remove from oven and allow to rest for 10 minutes prior to serving.
Top with parsley or chives for garnish.