Turnips are humble vegetables, reliable standbys of the wintertime market. At first glance, a turnip won't make you swoon in the way that a romanesco will, and it's true that the scent of a turnip is nowhere near as lovely as the scent of a Meyer lemon. The turnip, however, has more to offer than meets the eye.
For over four thousand years, turnips have been appreciated as a quick-growing, staple crop. Like other root vegetables, turnips are concentrated packages of nourishment and will keep for months under proper conditions. A young turnip, freshly harvested, is small, mild, and tender. It can be eaten raw, or pickled in rice vinegar and salt. As a turnip grows in size, it takes on some of the fieriness associated with its relative, the horseradish. Large turnips are best cooked until soft. They add a subtle zippiness to soups and stews. I am particularly fond of eating turnips with roasted meat -- the vegetable's liveliness brings out the sweet, earthy qualities of the roast.
Most supermarkets will carry turnips, but often they have been stored for a while and can be woody or tough. Asian markets and farmers' markets are terrific places to look for just-dug turnips. The most common varieties you'll find are Tokyo Market, an all-white turnip that is perfect thinly sliced in salad, and Purple Top Globe, a larger turnip with purple shoulders. Keep your eyes peeled for Scarlet Ohno turnips--you can't miss their neon pink skin.
If you are lucky enough to find turnips with their green tops still attached, consider sautéing the leaves in salted butter and olive oil. Turnip tops are an excellent source of calcium and vitamins K, A, and C. Underrated and overlooked, turnips can be nutritious, versatile, and surprisingly flavorful.
Only four ingredients (plus salt and pepper) are needed for a luxurious gratin. Potato is the classic main ingredient, but turnip makes for a delicious variation.
2 cups heavy cream
2 small cloves garlic, peeled
Unsalted butter, for the baking dish
1½ pounds turnips, peeled if the turnips are bigger than your fist
½ cup grated Parmigiano, Gruyère, or similar hard cheese
Kosher salt and freshly ground black pepper
Preheat the oven to 375°F.
Pour the cream into a small saucepan, add 1 clove garlic, and bring to a boil over medium heat. As soon as bubbles appear around the edges of the pan, turn off the heat and let the garlic-cream steep for a few minutes.
Meanwhile, rub the remaining clove of garlic across the inner surfaces of a 2-quart baking dish, and then butter the dish. Slice the turnips into 1/8-inch-thick rounds. (A mandoline makes this step quick and easy, but a sharp knife will do.)
Place one third of the turnip slices in the baking dish, overlapping them slightly, in an even layer. Season with ½ teaspoon salt and several grinds of pepper. Make another layer with the second third of the turnip slices, and season with ½ teaspoon salt and several grinds of pepper. Arrange a final layer of turnip slices on top, making this layer especially beautiful because it will be visible. Sprinkle it with ½ teaspoon salt and several grinds of pepper, then pour the garlic-cream over the turnip layers. Using your fingers or the back of a large spoon, press down on the turnips. The garlic-cream should just cover them. Wrap a piece of foil over the dish, and bake for 30 minutes.
Remove the foil cover, sprinkle the Parmigiano cheese over the top, and return to the oven. Bake for another 30 minutes, or until the turnips are tender and the top of the gratin is golden brown. Let the turnip gratin rest for about 15 minutes before serving.