The Global Chef: From a humble history, citrus enlivens, sharpens, multitasks

May 8—Citrus is unique among fruit. Every variety of this abundant cultivated species come from only three native South and East Asian ancestors: citron, pommelo and mandarin orange ... citrus that researchers believe existed in China 7 million years ago. All modern citrus fruits are the result of crossing these three original species.

Additionally, citrus fruits enliven stews, soups, vegetables and sauces; prevent browning (avocado, pear, apple), balance fat (vinaigrette), cure seafood (seviche), add a tangy bite to marinades and flavor a multitude of desserts from key lime and lemon meringue pie to sorbettos and cakes. Frequently a squeeze of lemon, lime or grapefruit is just the flavor you need to finish a dish, but one you might forget.

The scent of citrus blossoms that fill the air in March and April are so heavenly you might want a tree in your home. Start with a dwarf lemon or kumquat in a south window and transfer the plant outside every summer.

No fruit can beat the ideal sweet-tart blending of a bright, juicy citrus fruit. They are a sure way to sharpen and invigorate winter-weary meals and a refreshing way to chase the heat. Winter stews and roasts, braised fish, salsas, guacamole, vegetable slaw or a pies, cakes, drinks and puddings all benefit from a dose of citrus. Toss sliced kumquats into a pork roast or icy vodka. Section pink grapefruit for salsa and serve it on grilled chicken. Peel a mix of citrus for a citrus-olive-red onion salad or toss them with greens.

Grill or roast citrus slices or halves for a unique flavor treat. Brush halved or sliced citrus with oil, sprinkle with salt, and grill until tender for an extra juicy, smoky, luscious flavor. Caramelization transforms the citrus; it lends a rich sweetness and mellows acidity. Drizzled over grilled seafood or poultry, the juice is concentrated, and milder than freshly squeezed citrus.

Citrus zest is the thin, colorful outer layer of the citrus peel. Packed with aromatic oils, citrus zest provides an intense floral citrus flavor. Zest is useful to deepen the flavor in baked goods, sauce and stews or soup. Don't waste that lemon or orange peel: zest it before juicing and freeze the zest with a bit of juice. To freeze citrus fruit, peel and separate into segments. Lay peeled segments on a tray covered with parchment paper and freeze. Once the fruits have frozen, store them in a zipper bag in the freezer.

Citrus pith is the thicker, spongy white inner layer. It's very bitter, but full of vitamin C. Chefs avoid it when zesting or segmenting fruit. Moroccan cooks have developed a wonderfully unique way to preserve whole lemons in salt and fresh lemon juice. The salt neutralizes bitterness from the pith and softens it to chewy, salty tenderness, great as a garnish in salads, soups, Thai curries or stews.

If you juice citrus regularly, invest in an electric citrus juicer: it will wring out every drop of juice, separate seeds and pith from juice and save your wrists. A wooden reamer, fork or hand juicer also work fine. Roll the whole fruit with your palm before juicing to yield more juice.

Despite encroaching disease and pests, citrus is a constantly expanding market.

"Citrus is competitive," says citrus breeder and geneticist Fred Gmitter (to National Geographic magazine). He notes how global researchers strive to develop certain citrus that are sweeter, seedless and easy to peel.

"In the near future you'll see a lot of outside-the-box new stuff."

The bright orange, green and yellows of tangerines, lemons, limes, kumquats, oranges, blood oranges, grapefruit and clementines seem to embody the warmth of the sun. To think that all this pleasure arose from just three ancestors, a bit of crossbreeding and a lot of time.

Roasted Citrus

You may balk, but whole roasted citrus is completely edible. Serve tossed in salad or cooked vegetables or pair with avocado, roasted poultry or fish.

Yields about 6 slices per fruit

Medium-size lemons or oranges

Olive oil

Preheat oven to 400 degrees F. Line a sheet pan with parchment or a silicone mat and brush with olive oil, or brush a roasting pan (large enough to hold citrus slices) with olive oil.

Scrub citrus, rinse well and dry. Slice fruit crosswise about 1/8- to 1/4-inch thick. Remove seeds. Arrangecitrus slices into prepared pan in a single layer, brush with oil and season with salt.

Roast citrus slices until they soften andbrown on the bottom, about 20 minutes. (You may flip slices and roastuntil both sides are soft and golden.) As the citrus starts to roastit releases juices that evaporate and the fruit browns and caramelizes. Remove pan from oven and arrange slices on platter. Serve warm.

Fennel-Orange Salad with Red Onion and Olives

This popular Sicilian salad is made with blood oranges when they are in season.

Yields 6 servings

1 small red onion, peeled

2 large navel oranges

2 to 3 small fennel bulbs, 1 pound trimmed

1/2 C. pitted kalamata olives

3 T. extra-virgin olive oil

1-1/2 T. fresh lemon juice

3/4 t. kosher salt

1 T. torn fresh mint leaves

Freshly ground black pepper

Slice onion in half top to bottom and remove stem and root. Thinly sliver half of the onion. Place sliced onion in a bowl covered with very hot tap or boiling water 5 minutes. Drain and rinse with cold water. Drain on paper towel.

Slice both ends off an orange. Set orange on cutting board, a cut side down. With a sharp knife, cut away the peel by slicing around the curve of the orange from top to bottom. Slice orange crosswise into 1/4-inch thick slices. Remove seeds. Repeat with second orange. Arrange overlapping orange slices on a deep platter or shallow salad bowl.

Slice fennel in half top to bottom. Lay each half on cutting board and trim away most of the core. Thinly slice fennel halves lengthwise and toss in a bowl with reserved onion. Slice olives in halves or quarters lengthwise and toss with fennel and onion.

In a small bowl, whisk together the extra-virgin olive oil, lemon juice and salt. (The recipe may be prepared up to this point several hours in advance. Wrap and refrigerate the fennel mixture. Tear mint just before serving.)

Arrange fennel mixture over oranges and sprinkle with mint.Drizzle dressing evenly over salad. Sprinkle with freshly ground black pepper. Serve immediately.This salad pairs well with grilled poultry or seafood.

— Adapted from "Fine Cooking"

Broiled Lemons with Greens

Lemons excel when the cook balances them between salty and sweet.

— Adapted from "Lemon Zest," by Lori Longbotham

Yields 6 servings

2 lemons, cut into paper-thin slices and seeded

2 T. sugar

1 t. salt

4 C. baby arugula, washed and spun dry

4 C. finely sliced romaine hearts, washed and spun dry

2 to 4 T. olive oil

Freshly ground black pepper

Freshly squeezed lemon juice

Combine lemons, sugar and salt in a medium bowl and let stand for 1 hour. Stir occasionally. Heat broiler. Place lemons on a rimmed baking sheet in a single layer and spoon liquid in bowl over them. Broil about 5 inches from heat until lightly browned, 3 to 4 minutes. Turn pan to brown lemons evenly.

Meanwhile, place greens in a serving bowl. Add hot lemons and their liquid, oil and pepper; toss well. Season with salt and additional lemon juice, to taste. Serve immediately.

Slow-Roasted Pork Shoulder with Kumquats and Chiles

The kumquats bestow a lovely light citrusy flavor.

— Adapted from "Down South"

Yields 8 servings

6-lb. boneless pork shoulder

1/4 C. kosher salt

1 T. ground coriander

1 T. paprika

1 T. sugar

1 C. thinly sliced kumquats

10 garlic cloves, thinly sliced

4 jalapenos, thinly sliced into rounds

2 medium onions, sliced into 1/2-inch rounds

Preheat oven to 300 degrees F. With a chef's knife, make about 15 1-inch incisions on each side of the shoulder.Combine salt, coriander, paprika and sugar in a small bowl. Evenly season pork all over with it. Push kumquats, garlic and jalapenos into the center cavity and the incisions with the spice mix.

Cover bottom of a large shallow roasting pan with sliced onions. Place shoulder atop onions. Place pan in oven. Roast, basting pork with fat and juices that collect in the pan, until the meat is very tender and caramelized, about 1-1/2 hours.

Reduce oven temperature to 275 degrees F, add 4 cups water to the pan, and cover pork with foil. Bake 7 more hours, until pork is pull-apart-with-a-fork tender.Remove pork from pan. Pour pan juices and scrapings into a saucepan. Skim fat from the top and discard. Simmer juices over medium heat to reduce liquid by half.

Serve pork on a platter with the reduced sauce poured over the top. The pork will be very tender.

Nancy Allen's Preserved Lemons

Traditionally made, Moroccan preserved lemons are quartered through their skin to within 1/2-inch of bottom and top so they hold together. Stuffed with salt, they are packed into a glass jar and sealed. Within a few days, lemon juice will fill the jar. The method below, with cut and squeezed lemons, is a way to get a higher yield of skin and to ensure that the lemons will be completely covered with lemon juice from the start. The salty juice and the saturated, tasty skin of the lemon are both delightful. Slice or dice the skin and toss in hot rice, salads, dressings, stuffings or as soup or stew garnish.

— From "Discovering Global Cuisines" by Nancy Krcek Allen

Yields 1 quart

2 oz. kosher salt, 6 T., divided

7 medium lemons, preferably organic

Pour 1 tablespoon salt on the bottom of a wide-mouth glass 1-quart canning jar and set aside. Slice lemons in half through their equators and squeeze lemons to juice them. Set juice aside in a measuring container with a spout. It should yield about 1-1/4 to 1-1/2 cups.

Divide 3 tablespoons salt among the lemon halves, and rub their insides. Pack lemon shells into jar. Sprinkle remaining 2 tablespoons salt over lemons and pour fresh lemon juice over the salt until the lemons are covered, leaving 1/2 to 1-inch headspace. Seal jar tightly with plastic lid or a piece of plastic wrap and metal lid.

Set jar on non-reactive pan to catch overflow juices. Leave lemons in a warm spot 4 to 6 weeks or longer to mature. Shake jar daily to distribute salt. Check lemons for tenderness, and refrigerate when lemon skins are softened and tender. If juice has absorbed and lemons are not covered with juice, add more freshly squeezed juice. The lemons will improve in flavor up to 6 months. Preserved lemons keep refrigerated for 1 year.

Before using lemons scoop out and discard inside pulp. If lemons develop a white yeasty-looking mold, rinse it off. It is not harmful. Slice or dice lemon shells and toss into stews or soup to simmer no more than 10 to 15 minutes. Or toss uncooked diced preserved lemon with with olives or hot rice.

Nancy Krcek Allen has been a chef-educator for more than 25 years and has taught professional and recreational classes in California, New York City and Michigan. Her culinary textbook is called "Discovering Global Cuisines."