The simplest ingredients, with special treatment, often are transformed into delicious edibles. For example, the humble peel of winter citrus -- orange and grapefruit in particular -- is grated for its aromatic zest, or occasionally cut into fine strips to garnish fruit salads, custards or mousses.

However, when the citrus flesh is stripped of its peel, boiled several times and infused with a sugar syrup, the results are even more memorable -- a delectable confection, candied fruit peel.

The fragrant peel, with a bittersweet quality, is an irresistible sweet to offer with coffee, just as you would any type of sweetmeat, and glazed peel adds a charming decorative touch when placed atop fruit tarts, sorbet or marinated fruit. It's wonderful to nibble on right after a rich winter meal and equally refreshing when served along with pastries at afternoon tea.

The recipe I have developed for candied fruit peel produces the type that is semi-firm and permeated through and through with the fruit syrup. This peel has a slight edge of chewiness (in the outer rind), just for textural contrast.

There are three basic, and very easy, stages that turn raw peel into a glazed candy. The first step is the cooking of the peel to soften it and to remove much of the inherent bitterness. Quarter sections of peel and pith together are cut off from the fruit, dropped in a pot of cold water and brought to a boil, then drained once the water has boiled. This process is continued two more times; during the last boil, the peel continues to cook at a lively bubble for about 5 minutes.

At this point the peel will be quite tender and so very receptive to a sugar syrup bath. While the peel is boiling for the third time, you begin the second step -- which is to make a simple syrup. The drained peel is cut into thin, thin strips and added to the syrup to simmer and absorb the syrup. The white pith (just under the peel) will turn almost translucent when it has taken in the syrup. When the peel is translucent and most of the syrup has been used up, the second step has been completed.

The third stage is one of scattering the peel on cookie sheets to dry; after a few hours, the peel is then lightly rolled in granulated sugar. I prefer to enrobe the peel in sugar several hours later, as opposed to turning the peel in sugar as it comes out of the sugar syrup bath; in this way, the peel does not absorb too much sugar, and the outer edges are merely dusted over with a fine haze of sugar granules.

For the recipe that follows, work either with grapefruit peel or orange peel, as combining both in one batch makes for uneven results. This addictive sweet requires little effort on the part of the cook and is a very good way to use up the last of the season's oranges and grapefruit. CANDIED ORANGE OR GRAPEFRUIT PEEL (Makes about 3/4 pound of peel)

* Use thick-skinned naval oranges or white grapefruit for making the best peel. Fruit peel absorbs the sugar syrup most readily when the rinds are very thick.

* FOR THE FRUIT:

4 thick-skinned naval oranges, or 2 thick-skinned grapefruit, quartered

FOR THE SYRUP:

1 1/2 cups granulated sugar

3/4 cup water

1/4 teaspoon cream of tartar, or 1/2 teaspoon light corn syrup

TO FINISH:

About 1 cup granulated sugar

*To prepare the fruit: With your fingers, bend back the colored peel and thick white pith from each quarter of orange or grapefruit. (Use the fruit flesh for fruit compote or for snacking.)

Place the quarters of peel in a large water-filled kettle and bring to a boil. Drain, removing the peel to a side dish. Refill the kettle with cold water, add the peel and bring to a boil again. Drain. Put the peel in the kettle for the third time, fill with cold water and bring to a boil. When the water reaches a boil, continue boiling for 5 minutes.

Drain the peel thoroughly, and when the peel is cool enough to handle, cut into 1/4-inch thick strips. The thinner the peel, the more elegant the confection.

While the fruit peel is boiling, make the syrup: Put the sugar, water, cream of tartar (or corn syrup) into a heavy 4-quart casserole. Cover and cook over low heat until every granule of sugar has dissolved. Uncover the pot, add the strips of peel and cook at a rapid simmer for about 10-15 minutes, or until the peel absorbs at least half of the syrup. Turn the peel in the syrup often. Cooked peel, properly glazed, has translucent undersides; the syrup will reduce into a slightly sticky coating.

Transfer the peel, using two forks, onto large cookie sheets, scattering the pieces so that they are not heaped on top of one another. Keep the strips as separate as possible. Let stand 2-3 hours to firm up the peel.

When the peel is barely tacky to the touch, lightly roll the peel in the granulated sugar to finish. Transfer the strips to metal cooling racks; let stand for about 2 hours before storing in covered tins.