Potatoes au gratin or simply gratin made with potato, which is an easy dish produced by layering sliced potatoes, heavy cream, and grated cheese, is widely considered to be the most comforting dish ever created. This recipe for potatoes au gratin was shared with me by my amazing friend Kelly Santoro, and it's very identical to the one I used while I was attending culinary school. The dish is ridiculously delicious. The recipe asks for grated cheese and heavy cream to be layered on top of potatoes that have been cut very thinly and then baked in a casserole. After that, the dish is placed in the oven and roasted until the cream congeals and creates a rich, creamy sauce that covers the potatoes. Despite the fact that I assert that the meal is worthy of being celebrated on a special occasion (which it is! ), the truth remains that just consuming the food is in and of itself a momentous occasion.
Before moving on to the more in-depth instructions, we need first address a few points pertaining to the components: When making an au gratin dish, the best potatoes to use are russet potatoes since they have the highest starch content and result in the creamiest sauce. There is a possibility that you may feel compelled to switch out the cream for milk or half-and-half. I beg you to abstain! This is one of those recipes that really does call for the use of heavy cream in order to get the desired consistency. Instead of using regular parmesan, genuine Parmigiano Reggiano should be utilized. The skin, which bears several impressions of the brand, is the best indicator of whether or not the product in question is authentic. (If the cheese has been grated before, it should not be called "Parmesan," but rather "Parmigiano Reggiano," since this is the correct name for the cheese.) In the event that you are unable to get it, Pecorino Romano is an excellent substitute. POTATOES AU GRATIN RECIPE To begin, slice the potatoes into uniformly thin and uniformly sized pieces as best you can. You could use a mandoline slicer if you have one, but I don't even bother to use mine.
(Here's a helpful hint: If you're trying to cut a potato that's a little wobbly, first make a thin incision down the potato's length, and then set it cut-side down on a cutting board so that it lays flat.) In a large bowl, toss the potatoes with the salt and pepper, then set the bowl aside. Check to see that all of the potatoes have the same amount of coverage. A baking dish with a capacity of 2 quarts needs to be buttered. Place a few potato slices on the bottom of the plate in a single layer with their edges overhanging each other. Spread a quarter of the melted cheese on top of the potatoes. Pour one-fourth of the cream over the top of the cake. Make four layers by layering the remaining potatoes, cheese, and cream in the same manner as before. Any more cream that was not used should be poured on top. Put in the oven and bake uncovered for 60 to 75 minutes, or until the potatoes are soft when pierced with a fork and the top is golden brown. 
If you would like the baking dish to have a little darker browning, you may set it under the broiler for one to two minutes; however, you must keep a close eye on it to ensure that it does not burn. When the dish is finished baking, the top layer of potatoes should have achieved a wonderful golden coloration. If you're using it, sprinkle some fresh thyme leaves on top of the dish before serving. (Note: If you wish to double the recipe for a large party, you should bake it in two baking pans that are each 2 quarts in capacity rather than in one dish that is much bigger for the best results. Because of this, the potatoes will cook more evenly in this manner.) Ingredients
- Butter to grease the baking dish
- 2½ pounds Russet potatoes (3 to 4), peeled and sliced very thin
- 1½ teaspoons salt
- ¼ teaspoon freshly ground black pepper
- 1 cup (4 oz) finely grated Parmigiano-Reggiano
- 2¼ cups heavy cream
- Fresh thyme, for serving (optional)
Instructions
- Put a rack in the middle of the oven, and preheat it to 350 degrees Fahrenheit. When greasing a baking dish that is 8 inches wide (or 2 quarts in capacity), butter should be used.
- In a large mixing bowl, give the potatoes a good toss with the salt and pepper so that they are evenly coated.
- Some of the potato slices should be arranged in a single layer with the edges overlapping in the prepared baking dish. The dish should then be placed in the oven. Following the step of sprinkling the potatoes with a quarter of the cheese, a quarter of the cream should next be added on top of the potatoes. Repeat the procedure three more times to end up with four layers of potatoes, cheese, and cream. Any more cream that was not used should be poured on top.
- Put in the oven and bake uncovered for 60 to 75 minutes, or until the potatoes are soft when pierced with a fork and the top is golden brown. The meal should be let to rest on the counter for about fifteen minutes. Before serving, if you choose to use it, finish by sprinkling some fresh thyme on top.
- It is possible to start preparing the components of this dish as early as a day in advance. Keep the potatoes in the refrigerator after protecting them from oxidation by wrapping them tightly in plastic wrap and pressing the wrap firmly against the potatoes. Finish baking the dish just before you serve it. Although the potatoes on top will continue to get a darker brown after being refrigerated, this should not be seen once the casserole has been baked.