I first discovered this dish when I was preparing for a friend’s Thanksgiving dinner. I’d been told to bring a potato dish, and I wanted to bring something special. I stumbled onto a version of root vegetable gratin on Smitten Kitchen and was inspired to create my own variation. It turned out great --- tasty and unique, indulgent, but nutritious. Now I make it regularly for dinner alongside a simple roast chicken breast.
The blend of starchy vegetables here adds color and texture to the classic potatoes au gratin. I’ve cut out alliums except for garlic because they tend to overpower the delicate vegetal flavors. Pecorino Romano’s strong, salty taste is the perfect counterpoint for the vegetables’ sweetness.
Root Vegetable Gratin
10
30 minutes
1 hour, 15 minutes
1 hour, 45 minutes
1 1/2 cups (360 ml) heavy cream
1 cup (240 ml) chicken broth
2 cloves garlic, minced
1 teaspoon (1 g) dried thyme
2 teaspoons (14 g) salt
1 teaspoon (2 g) pepper
3 medium sweet potatoes, peeled and thinly sliced
6 small Yukon gold potatoes, peeled and thinly sliced
4 turnips, peeled and thinly sliced
3 large celery roots (celeriac), thinly sliced
2 cups (200 g) Pecorino Romano
2 cups (250 g) bread crumbs
2 tablespoons (28 g) butter, melted
Heat oven to 350 degrees Fahrenheit (175 degrees Celsius). Butter a 13-by-9-inch baking dish.
Mix together thyme, salt, pepper, cream and chicken broth in a large bowl.
Layer root vegetables in dish, in the order listed, creating a single layer of each vegetable. Sprinkle with 3/4 cup cheese and pour 3/4 cup cream mixture over the top.
Repeat, making another single layer of each vegetable, adding another 3/4 cup cheese and 3/4 cup cream mixture.
Layer the remaining vegetables on top. Pour in the rest of the cream mixture.
Mix remaining 1/2 cup cheese with melted butter and bread crumbs and sprinkle on top. Bake for 1 hour, 15 minutes, until vegetables are tender. Cool for at least 10 minutes before serving.
Pro tip: This gratin has creamy but relatively thin sauce. If you prefer a thicker coating, replace 1/2 cup of the cream with full-fat sour cream.
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