I have good news and bad news. The bad news is that a vegetable gratin is not a one-dish recipe. There is certainly a lot of appeal in the idea that you can stack sliced raw vegetables in a casserole, pour over some cream or stock, top them with cheese, and bake them to perfection—without having to wash anything along the way but your cutting board and chef’s knife. Unfortunately, you will be waiting a very long time if you take this tack. Baking with liquid is simply not a very effective way of softening raw vegetables, unless you have sliced them paper thin, scalded your liquid (which requires an extra dish already), and taken vigilant care not to layer them too thickly.
If you are not fastidious enough to commit to these steps—or if, God forbid, you want to include more than one kind of vegetable in your gratin—you must cook your vegetables before layering them in the pan. Granted, this requires a few more dishes and a few more steps than your typical casserole. But—and this is the good news—if you’re willing to pre-cook your vegetables, you are guaranteed a peerless gratin containing enough complementary textures and flavors to keep you enthralled till the last bite. Such a gratin might not be a one-dish recipe, but it’s certainly a one-dish meal.
A superlative fall vegetable gratin has four crucial components. For autumnal panache, you need a carbohydrate-rich, slightly sweet vegetable: either winter squash or a root vegetable like sweet potato, carrot, or parsnip. You need a green vegetable to give the thing a healthy kick and to keep it from getting bogged down in starchy richness. (Collards are wonderful—always hearty, never slimy—but other leafy greens are acceptable, too, as are broccoli and Brussels sprouts.) Thirdly, you need a cooked grain. Hear me out: Many gratins call for additional starch in the form of breadcrumbs, but breadcrumbs are not only flavorless, they also contribute no structural integrity whatsoever. Grains form a solid foundation for any gratin, and they leave no doubt in anyone’s mind that what you are looking at is a main course, not a side dish. Finally, you need a melting cheese, both for its awesome cohesive powers, and for the obvious reason that cheese is a universal improver of savory dishes.
Take the following recipe, then, as a formula rather than a strict prescription. The idea is to cook each component in the way that brings out its best qualities—this means roasting the squash, steaming the collards, and boiling the wild rice—and then to layer them together with the cheese and to bake the gratin just long enough to give it a crisp, browned surface. I will grant you that it looks a little complicated. But you know what else is a little complicated? Joanna Newsom songs. And as any fan of Have One on Me knows, putting a little time and effort into your enjoyment can be incredibly rewarding.
Butternut Squash, Collard Green, and Wild Rice Gratin
Yield: 8 servings
Time: About 1½ hours, partially unattended
¾ cup wild rice
4 tablespoons extra-virgin olive oil
1 small head of garlic
1 large butternut squash, peeled, seeded, and cut into ½-inch slices
1½ pounds collard greens
Oil for greasing the pan
8 ounces Gruyere cheese, grated
½ cup chopped hazelnuts
1. Put the wild rice in a medium saucepan with 3 cups water, 1 tablespoon olive oil, and a large pinch of salt. Cover and bring to a boil over high heat. Reduce the heat to medium-low and simmer until the rice is tender and has absorbed all the water, about 45 minutes.
2. Meanwhile, heat the oven to 425°F. Separate the head of garlic into cloves and peel each clove. Toss the garlic and butternut squash with 2 tablespoons of the olive oil and a little salt and pepper on a 13- by 18-inch baking sheet (or two smaller baking sheets). Roast, turning once or twice, until the squash is fully tender, 30 to 40 minutes. Remove, and reduce the oven temperature to 400°F.
3. While the rice and squash are cooking, remove the thick stems and ribs from the collard greens and discard them; cut the leaves into ribbons. Put the greens in a steamer over 1 inch of salted water in a large pot; cover the pot, bring the water to a boil, and steam the greens until tender, about 10 minutes.
4. Grease a 9- by 13-inch pan. Stir about half the Gruyere into the rice; spread the rice mixture into the pan. Arrange the collard greens on top of the rice and drizzle them with the remaining 1 tablespoon olive oil. Layer the squash and garlic on top of the greens, and gently mash them into the greens and rice with a potato masher or fork. Sprinkle the remaining Gruyere and the hazelnuts on top of the squash, and bake the gratin at 400°F until the cheese is melted and golden brown, 20 to 25 minutes. Serve hot or warm. (Store leftover gratin covered with foil or plastic wrap in the refrigerator for up to a few days.)