Yield: Serves 6 to 8 | Prep Time: 1 hour | Cook Time: 1 hour 30 minutes
When you think of root vegetables, you might think difficult and even fussy. But these aren’t! First of all, I like potato skins (and you may, too; they’re packed with flavor), so I skip peeling my potatoes. The other vegetables are quick to peel and roast just as fast. The best thing about this casserole is that it can be made ahead of time and reheated in the oven when you’re ready to serve. So when entertaining a crowd, you can make it in the morning, or even the night before.
INGREDIENTS
1 celery root, peeled
3 parsnips, peeled
1 large sweet potato, unpeeled
2 to 3 russet potatoes, unpeeled
1 red onion
1 tablespoon olive oil
1 tablespoon fresh thyme leaves
1 teaspoon salt
½ teaspoon freshly ground black pepper
2 tablespoons unsalted butter
3 garlic cloves, slivered
3 cups heavy cream
2 bay leaves
1 cup shredded cheddar cheese
½ cup grated Parmesan cheese
Rosemary sprigs, for garnish
DIRECTIONS
1. Preheat the oven to 400°F. Line 2 large baking sheets with foil and spray with cooking spray. Lightly coat a 9 × 13-inch baking dish with cooking spray and set aside.
2. Cut the celery root, parsnips, sweet potato, russet potatoes, and red onion into a uniform, large dice and place in a large bowl. Add the olive oil, thyme, salt, and pepper and toss to coat. Arrange the vegetables on the baking sheets in a single layer and bake for 45 minutes, turning halfway through the baking time. Remove the vegetables and lower the oven temperature to 350°F.
3. While the vegetables roast, melt the butter in a small saucepan over medium heat, add the garlic, and cook for 1 minute, until fragrant. Add the cream and bay leaves and bring to a low simmer, then remove from the heat and allow the flavors to steep, about 10 minutes.
4. Layer half of the vegetables into the baking dish. Top with half of the cheddar cheese and then add the remaining vegetables in an even layer on top. Remove the bay leaves from the steeped cream and pour the mixture over the vegetables.
5. Sprinkle the remaining cheddar and the Parmesan cheese over the casserole and bake for 45 minutes, until the top is golden brown. Garnish with rosemary sprigs and serve.