Little known in this country until about 15 years ago, balsamic vinegar has been warmly embraced by American cooks. We drizzle it on salads and steamed vegetables, sprinkle it on sautes and use it to marinate strawberries.

You can find an array of balsamic vinegars in most supermarkets, right next to the cider and wine vinegars. Prices in specialty stores can top $100 for a small bottle, so it helps to understand the origin and subtleties of balsamic vinegar.

Unlike most vinegars, which start with fruit juice or wine, balsamic starts with unfermented trebbiano grape must (crushed grapes). Cooked in big kettles, it turns to vinegar with the addition of a starter yeast. The color deepens and becomes more opaque and the flavor grows in complexity as the vinegar is aged in a series of barrels of different sizes and woods for 12 to 25 years.

Authentic balsamics come from Modena or Reggio Emilia, towns in northern Italy where this traditional style of balsamic vinegar was codified in the 18th century. The highest-quality vinegar is labeled "tradizionale" and sold in tiny bottles, to be used in very small amounts because it's so concentrated. Some chefs keep it in a spray bottle and spritz it on food.

Balsamics in the $3-$14 range are likely nothing more than ordinary wine vinegar with caramel added for coloring and sugar added to mimic the sweetness of the real thing. Chefs have a trick to "improve" them, however; They melt a teaspoon of dark brown sugar and stir it into a cup of the lesser vinegar.

For an everyday value, look for bottles labeled "Aceto Balsamico di Modena" at supermarkets. As an indulgence, seek out a small bottle of higher-grade balsamic (marked "condimento" or "tradizionale") from a specialty shop or an Italian market.

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BALSAMIC GLAZED VEGETABLES WITH PASTA

• 2 tablespoons olive oil

• 1 red bell pepper, cut into 1/4-inch-wide strips

• 1 yellow bell pepper, cut into 1/4-inch-wide strips

• 1 large onion, thinly sliced

• 1 garlic clove, finely chopped

• 2 zucchini, trimmed, cut crosswise into 1/4-inch-thick rounds

• 2 yellow summer squash, trimmed, cut crosswise into 1/4-inch-thick rounds

• 1/4 cup balsamic vinegar

• 8 ounces fusilli pasta (spirals)

• 1/4 cup Parmigiano-Reggiano cheese, grated

• Salt and freshly ground pepper to taste

Bring pasta cooking water to a boil.

Heat oil in large, heavy skillet over medium-high heat. Saute peppers, onion and garlic they begin to soften, about 4 minutes. Add zucchini and yellow squash and saute until tender, about 5 minutes. Add vinegar to skillet; boil until liquid is reduced to a glaze and coats vegetables, about 2 minutes. Season to taste with salt and pepper.

Meanwhile, cook pasta according to package directions. Drain well and add to the skillet along with the cheese; stir to combine. Season with salt and pepper to taste. Serve at once, passing extra cheese at the table, if desired. Makes 4 servings.

Per serving: 371 calories (24 percent from fat), 9.9 g fat (2.3 g saturated, 5.6 g monounsaturated), 5.5 mg cholesterol, 13.3 g protein, 59 g carbohydrates, 5.6 g fiber, 118 mg sodium.