A gratin may seem like something fancy, but it’s really quite easy! For some variety, I like to make a “potato plus two” gratin; but as an everyday side dish, this version is a bit lighter, in that it has less cream and less cheese than a traditional potato gratin.
In my most recent iteration of this dish, I combined Yukon gold potatoes with celery root and butternut squash. Although you can certainly use a mandoline to slice the vegetables thinly, it really is not too difficult just to use a cutting board and a sharp knife. If using a knife to slice the vegetables, cut them in half first so you have a stable base for making thin slices safely.
You can certainly experiment with this recipe and try other firm root vegetables or winter squash or even thin wedges of fennel. And if you have only potatoes and one other vegetable, that will be fine, too.
If you don’t finish it in one meal, leftovers can be rewarmed in the oven covered with foil, or in the microwave. The cheese may separate a bit, but it will still be delicious.
POTATO + 2 GRATIN
Cooking spray for the pan
1 pound Yukon gold potatoes
1 pound butternut squash, or other hearty vegetable
1 pound celery root, or other hearty vegetable
1 teaspoon salt, divided
1/4 teaspoon pepper, divided
3/4 teaspoon dried thyme, divided
1/2 teaspoon nutmeg, divided
1 1/4 cup heavy cream, divided
6 tablespoons grated Parmesan, divided
Preheat the oven to 400 degrees F. Spray a large gratin dish or baking pan with cooking spray.
Prepare the vegetables: Peel and slice thin. If using butternut squash, the neck is easier to work with, and you can save the rest to roast for another meal. A mandoline will work well here (but watch your fingers!) or if using a knife, be sure to cut all vegetables in half to provide stability and safety.
For the first two layers there is no need to be fancy. Take about a third of each vegetable and arrange in the prepared pan so that the vegetables are somewhat interspersed. Sprinkle with about one third of the salt, pepper, thyme, and nutmeg. Drizzle with about ¼ cup of the heavy cream and sprinkle two tablespoons of Parmesan over all. Repeat for the second layer. For the third layer, if you’re feeling fancy, try to arrange the vegetables in an attractive pattern, or just repeat what you did for the first two layers. It’ll be fine either way. Sprinkle with the remaining salt, pepper, thyme, and nutmeg, pour the rest of the cream over all, and sprinkle the last two tablespoons of Parmesan on top.
Bake in the preheated oven for 45 minutes. Allow to rest for 5 to 10 minutes before serving.