Roots : How to Roast a Root

Try this the next time you have an afternoon with absolutely nothing better to do: Take two potatoes, boil one and roast the other. Do the same thing with rutabagas, then turnips, parsnips, carrots, beets. . . . Just how much time do you have, anyway?

The results are startling. The flavors and textures of the roasted vegetables are so different from the boiled that you might think you’ve cooked two different plants. From the oven, the vegetables are intensely flavored with a crusty, chewy exterior and a puffy, light inside. From the pot, the flavors are softer and less definite; the textures more uniformly waxy or buttery.

While lightly cooked, bright, crisp vegetables might be just the thing for spring and summer, on a cold, rainy winter day, there’s nothing like the warm, soft, intensely “cooked” flavor of roasted vegetables.

It seems almost magical how cooking roots this way--toss the vegetables with a bit of seasoned olive oil or melted butter, put in roasting pan, roast--is so simple and can conjure up such complex and intense flavors.

Really, it all comes down to chemistry.

When any food is heated, a chain of chemical changes begins. One is called the Maillard reaction, after the turn-of-the-century French scientist Louis-Camille Maillard. Actually a series of reactions, the final stage occurs when amino acids and sugars--which are found in almost all foods--are heated together to around 335 degrees and the complex “roasted” smells and tastes we cooks call “browning” begin to be created. This is different from (and frequently confused with) caramelizing, which occurs when sugar alone is heated.

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Harold McGee, in a wonderful chapter on browning in his “The Curious Cook” (Collier Books: $13), even tries an experiment in which he heats corn syrup and adds the contents of an amino acid capsule of the type sold at health food stores. Depending on the specific amino acid (or combination of acids) used, the smells ranged from frying onions to roasting meat.

Of course, browning is impossible in a boiled vegetable. Water boils at 212 degrees--well below the threshold temperature. But it’s equally obvious that when vegetables are boiled, something has happened. When heated to an intermediate temperature (at approximately 200 degrees to 220 degrees), vegetables develop flavors that are buttery rather than roasted.

The textures of the cooked vegetables are also different. When starchy vegetables are heated, the closely bound, waxy starch molecules begin to absorb water and swell, resulting in a puffy, soft texture. Because root vegetables are so high in water (ranging from 79% for parsnips to 91% for turnips), this happens whether the vegetables are boiled or roasted.

But when starchy vegetables are roasted, something else happens. While the insides get puffy from absorbing the interior water, the outside gets crusty. This is caused not by heat alone, but by the circulation of air. When dry hot air circulates over the vegetable, its surface dries out, creating a crusty shell. (Remember how you feel when the Santa Anas blow?)

For another experiment, try roasting potatoes on a flat baking sheet and in a deep roasting pan of the type frequently recommended for turkey. What happens? While the potatoes on the baking sheet develop a fine crust, those in the roasting pan will be closer to boiled or steamed than roasted. The high sides of the pan prevent the air from circulating over the vegetables.

How does all this work in the real world? In general, roasted vegetables are sweeter, with a more concentrated flavor and a more varied texture. That is not always for the best. For example, in the brassica vegetables (such as rutabagas and turnips) roasting not only develops a browned sweetness, it intensifies the vegetables’ naturally bitter “horseradish-y” edge. Paired with a fatty, faintly sweet meat such as duck or pork, they work well, but by themselves they might be too assertive.

On the other hand, it would be difficult to find something bad to say about roasted potatoes. Little smooth-skinned potatoes--either red or white--cut in half and filmed with olive oil, become well-browned and crusty on the outside and fluffy on the inside, with a sweet, intense potato flavor. Carrots are also delicious, with a dark, sweet, concentrated taste.

“I roast root vegetables,” says Michael Roberts, former chef at Trumps restaurant and a cookbook author. “Why? Because they taste better that way. Think of the difference between a baked potato and a boiled potato, that’s the difference between any root vegetable cooked by wet heat or dry heat.”

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It’s something that is gaining converts. When first contacted about roasting root vegetables, Madeleine Kamman, director of the School for American Chefs at Beringer Vineyards in the Napa Valley, was dismissive: “A potato, maybe, but most things I personally would not roast. I would rather have my vegetables taste nice and fresh. If I cook carrots, I want to boil them in just a little Vichy water, very, very fast. Rutabagas, I cook them very deeply in water and then glaze them with veal stock. They are absolutely superior.

“But I know (roasting vegetables) is something a lot of kids are doing these days, and if they want to, why should I stop them?”

But, her curiosity piqued, Kamman--one of the best technical cookbook writers around--took to the kitchen for some experimentation. “You know, it is really very good,” she says now. “But the one thing people have to remember is that they must be cooked very thoroughly.

“What makes root vegetables like turnips and rutabagas bitter is sulfur and the mustard oil that is present in all the cabbage family. If you bake them, you intensify that because there is no water to diffuse that. This can be alleviated by using very young vegetables. Or, if you do use big vegetables, peel them deeply and blanch them two minutes in boiling water before you put them to roast. When you do the young ones--no more than an inch and a half across--they bake very beautifully.”

And as proof there’s nothing new under the sun (or soil), the experiment triggered a memory. “When I was a very little girl, coming from a quite modest family, very few of us had big ovens, so we couldn’t really boil very much. So when my mother cooked beets, she bought them already boiled. Then she would put them in the oven to dry them out and to concentrate the sugars. If you’ll look in ‘Making of a Cook’ (her first book), that is in there.”

This is inspired by, but drastically different from, a recipe in Madeleine Kamman’s “Savoie” (Atheneum: $24.95). Roasting the turnips first emphasizes their natural flavors. A final baking with cream smoothes everything out into something as beautifully turnip-y as you can imagine.

GRATIN OF ROASTED TURNIPS

3 pounds turnips, peeled and thinly sliced

2 tablespoons butter, melted

Salt

Freshly ground pepper

1/2 cup heavy whipping cream

1/3 cup fine, dry bread crumbs

1/2 clove garlic, finely chopped

1 tablespoon finely chopped parsley

In medium bowl, toss turnip slices with melted butter and season to taste with salt and pepper. Layer turnips on baking sheet and roast at 350 degrees for 20 minutes, or until browned. Watch carefully and do not let scorch. When turnips brown on both sides and puff, remove from oven.

In lightly buttered gratin dish or 1 1/2-quart baking dish, arrange turnips in overlapping layers. Pour cream over, lightly moistening. Combine bread crumbs, garlic and parsley and mix well. Spread across top of turnips and return to oven to bake until most of cream has evaporated and bread crumbs are golden, about 20 minutes. Makes 6 servings.

Each serving contains about:

227 calories; 374 mg sodium; 38 mg cholesterol; 11 grams fat; 28 grams carbohydrates; 5 grams protein; 2.01 grams fiber.

It is vital to use dark-orange sweet potatoes, frequently sold as yams, in this recipe. The lighter ones cook to a disagreeable yellow color and a dry texture more like a baked potato than a sweet potato.

GRATIN OF SWEET POTATOES AND BOURBON

3 pounds dark-orange sweet potatoes

Butter

Salt

1 cup heavy whipping cream

1 tablespoon bourbon

Freshly ground nutmeg

Roast whole sweet potatoes on baking sheet at 350 degrees until easily pierced with knife. Remove from oven and let cool.

Peel potatoes and cut into 1/4-inch-thick slices. Arrange in 1 overlapping layer in buttered gratin dish or 1 1/2-quart baking dish. Season to taste with salt.

In small saucepan over medium heat, reduce cream by 1/3. Add bourbon and whisk well. Pour over potatoes. Dust very lightly with freshly ground nutmeg and dot with butter. Bake at 350 degrees until browned and puffy, about 30 minutes. Makes 6 servings.

Each serving contains about:

415 calories; 133 mg sodium; 65 mg cholesterol; 19 grams fat; 56 grams carbohydrates; 5 grams protein; 1.93 grams fiber.

You can use this recipe from Susan Feniger and Mary Sue Milliken’s “City Cuisine” (Morrow: $19.95) as a model for other roasted root vegetable purees. Because the initial cooking is dry, the flavors are more intense. Replace the butter with a sufficient quantity of good chicken stock, and you have a nice, fat-free soup. CARROT AND RUTABAGA PUREE

1 large rutabaga

6 large carrots

5 tablespoons unsalted butter

1/4 cup water

Salt

Freshly ground pepper

Peel rutabaga and carrots and cut into 1/2-inch slices. Combine with butter, water and salt and pepper to taste in baking dish. Bake at 350 degrees until tender, 15 to 20 minutes. Finely grind vegetables in food processor. Adjust seasonings to taste and serve hot. Makes 6 servings.

Each serving contains about:

93 calories; 55 mg sodium; 26 mg cholesterol; 10 grams fat; 2 grams carbohydrates; 0 protein; 0.26 gram fiber.

OK, so these beets aren’t truly roasted (jacketing them in foil results in something halfway between roasting and steaming), but this technique does result in more intensely flavored beets. ROASTED BEET SALAD

3 pounds medium beets, with greens

2 tablespoons extra-virgin olive oil

2 teaspoons balsamic vinegar

1 teaspoon finely minced garlic

Coarse sea salt

Freshly ground pepper

Separate greens from beets and set aside. Tightly wrap all beets together in foil pouch. Roast at 350 degrees until beets can be evenly pierced with knife, about 40 minutes. Remove and set aside to cool.

In lightly salted boiling water, cook beet greens just until tender. Remove, squeeze dry and cut in fine strips.

When beets are just cool enough to handle, remove from pouch, remove stub of stems and rub peel away. Peel should come away easily and cleanly. Thinly slice beets and combine with chiffonade of greens.

In small mixing bowl, combine oil, vinegar and garlic. Pour over beets and greens and toss to mix. Do not overdress. Season to taste with sea salt and pepper. Makes 4 servings.

Each serving contains about:

209 calories; 316 mg sodium; 0 cholesterol; 7 grams fat; 34 grams carbohydrates; 5 grams protein; 2.65 grams fiber.

This is a Friday night dinner. It’s not really a recipe so much as a loose outline. I’ll use almost anything in my refrigerator leftover from the growers market. There are a few exceptions--beets will bleed all over and stain everything a deep red, and artichokes become far too bitter. This is wonderful when served with a simple roast chicken.

MARKET MIX

2 pounds baby red potatoes, halved

1 bulb fennel, trimmed and cut in thick wedges

1/2 pound brown mushrooms, cleaned and quartered

6 whole garlic cloves, peeled

1 sweet red pepper, stemmed, seeded and cut in thick wedges

1/4 cup olive oil

Salt

Freshly ground pepper

Combine potatoes, fennel, mushrooms, garlic and red pepper in large, shallow-sided roasting pan. Pour 1/4 cup olive oil over and season to taste with salt and pepper. Toss well to coat all vegetables.

Roast at 450 degrees 20 to 30 minutes without stirring. Shake vegetables to loosen from bottom and return to oven another 20 minutes, stirring once or twice during last 10 minutes. Potatoes should be browned and crusty. Makes 6 servings.

Each serving contains about:

221 calories; 63 mg sodium; 0 cholesterol; 9 grams fat; 32 grams carbohydrates; 5 grams protein; 1.12 grams fiber.

Food styling by MINNIE BERNARDINO and DONNA DEANE