“What’s a potato gratin?” “It’s like the mac & cheese of the potato world.” “Really?” “Yeah, seriously.”
Yup – I totally had that conversation last week. But layered with cheese, simmered in milk, and beautifully browned with a crunchy crust, the classic potato gratin really does bear resemblance to a baked macaroni and cheese dish. The fork-tender slices of potato glued by savory Gruyère and a golden crust worth fighting over both make this dish a winner!
2 to 2.5 lbs potatoes (yukon golds are best but any will do)
4 oz gruyere cheese
1.5 cups of milk (whole, low-fat, nonfat… your choice)
Salt & pepper
Butter, about 2 tablespoons plus a thin pat for greasing the pan
1 medium onion, chopped
Preheat the oven to 350 degrees. Wash and peel the potatoes.
Being very careful with a knife (or using a mandoline if you have one), slice into rounds anywhere from paper-thin to no thicker than about 1/8th inch thick. Just be as consistent as you can, for even cooking.
Grate the cheese into a bowl and set aside.
In a small pan, heat the butter until it just starts to bubble and brown. Add in the onions and season with salt and pepper. Saute until translucent and sweet – about 5 minutes. Once they’re done, set aside to cool off.
Butter a 9 x 13 pan (or a 9 x 12 gratin dish) generously on the bottom and be sure to work up the sides as well. Arrange potato slices in a single layer, allowing the slices to overlap a bit. Season with fresh cracked black pepper and sprinkle lightly with cheese. The gruyere I buy comes salted so I go easy on the added salt. Be sure to reserve about 1/3 of the cheese for the very top crust layer. Continue layering with potato, black pepper, and cheese.
After about 3 or 4 layers, arrange the next potato layer. Top with the sauteed onion, spreading to evenly distribute as best you can. Continue with another potato layer and repeat as before.
Use up all of your potato slices or as many as it takes to make about 8-10 layers, leaving one last layer of just potato. Fret not if you have extra lonely slices – you can reserve these leftover slices for making potato chips!
Pour the milk over the prepared gratin, letting it seep between the layers. Finally, top with the reserved 1/3 of cheese and bake for about 45 minutes to one hour, or until everything gets bubbly and the crust becomes a gorgeous golden brown.
Slice into squares and serve hot. We generally cut the 9 x 13 pan into sixths but it can easily serve 8 if part of a larger meal.
Some nights we’ll eat the gratin on its own paired with a freshly tossed salad… and other nights, we’ll start sizzling up some steaks when the gratin is about 15 minutes out from being done. As a side or as a (relatively) light main, this potato gratin is comforting and hearty dish that’s sure to please!
Oil (olive or vegetable)
Leftover gratin slices
Pour enough oil into a pan (or the small pot you used to saute onions if you want to save on dish-washing) to come up about 1/2 inch. Heat until a small drop of water dripped into the oil fizzles away (if it splatters, and be careful if it does, turn down the heat and let the oil cool a bit).
Drop in a few slices, making sure to not crowd the pan. I like my chips nice and browned – this will take a few minutes. Watch them carefully though! They can go from toasty to burnt in the blink of an eye.
Transfer toasty chips to a paper towel lined plate to drain. Sprinkle on a bit of salt (or seasonings of choice!) right when you take the chips out of the oil so they will adhere better.