Say you're making a roast chicken. Or a nicely marinated pork tenderloin. Or maybe a beautiful, thick steak. You take it out of the oven -- so fragrant and sizzling -- pick up your favorite knife and start slicing.

Congratulations. You've just ruined that beautiful meat.

Next time, give that meat a rest. Start slicing right after cooking ends, and this is what you'll get -- a big pool of juice on the plate and meat that tastes dry and tough. Let it sit for five or 10 minutes (or as much as 15 minutes for a whole chicken or 20 minutes for a large roast) and your meat will be as it should be -- juicy and tender.

There's a scientific reason for this. As meat cooks, the protein fibers tighten and contract, squeezing out the juices. The blast of heat on the surface of the meat, meanwhile, drives this liquid toward the center. When you slice into that pork roast right out of the oven or that flank steak just off the grill, all those juices pooled in the center come pouring out.

But, says food science expert Robert Wolke, good things come to those who wait. Wolke, author of "What Einstein Told His Cook" (W.W. Norton, 2002) and The Washington Post's Cooking 101 column, explains that letting the meat settle after roasting or grilling allows the protein fibers to partially relax again and the juices to redistribute themselves throughout the meat. As a result, less juice runs out when you slice the meat and the meat tastes better. Resting also allows the meat to firm up, making it easier to carve thin slices.

The other thing to remember, cautions Russ Parsons in "How to Read a French Fry and Other Stories of Intriguing Kitchen Science" (Houghton Mifflin, 2001), is that "just because you've removed something from the heat doesn't mean it has finished cooking."

As the meat rests, the stored heat at the surface continues to cook the middle of the meat, causing the internal temperature to rise as much as 10 degrees. Try it next time -- take a roast chicken out of the oven and immediately insert an instant-read thermometer in the thickest part. You'll see the temperature slowly rise as the center continues to cook. Meat, therefore, should be taken out when it's slightly underdone, or it will become overdone as it rests.

There's another reason to give meat time to rest. "Yelling time," Gillian Clark says bluntly. The chef of Washington's Colorado Kitchen and the mother of two says there's food science and mom science. Mom science says you need to factor in the time that you yell for the kids to come to dinner and they ignore you because they're IM-ing their friends or quarreling over the TV.

So, for instance, if you want perfect roast chicken, you take it out of the oven when it's almost done -- say, 150 to 155 degrees on an instant-read thermometer. You let it sit, tented with foil, and yell for the kids to come to dinner. As the chicken sits, says Clark, the temperature will rise to 160 to 165 degrees, which she considers ideal for poultry. (Federal food safety guidelines for absolute certainty recommend 170 degrees, however.) Meanwhile, you finish tossing the salad, or quickly saute some vegetables. You yell for the kids again. And again. By the time they finally show up, set the table and get settled, the chicken has rested about 10 to 15 minutes. When it's carved, it's perfect.

At her restaurant, Clark's "yelling time" turns into "walking time." She has to consider not only resting time for her entrees, but also what chefs call walking time -- the time it takes the waiter to walk over to get the plate from the kitchen and then walk it to the customer. This is especially important with Clark's signature roast chicken with herb gravy, a dish she alters at her peril. About a year ago, she took it off the menu and her customers threatened an uprising. It hasn't strayed since.

There's another term for the heating that continues as food rests. Chefs call it carry-over cooking, says Brian McBride, chef at the Melrose restaurant in the Park Hyatt Hotel downtown. The residual heat in the food, or in the pan, carries over from the stove and allows a final few minutes of cooking to finish the food. Chefs use this final "push," as it's also called, to time things exactly.

"You want a three-minute egg? Take it out at 21/2 minutes and let it sit. It will continue to cook and you'll have a perfect egg," says McBride. A thick piece of fish works the same way. "Grill a salmon steak for just under 10 minutes and then let it sit [in a warm place or tented with foil]. The residual heat will finish cooking the center," he says.

McBride says home cooks can use carry-over cooking to get perfect vegetables. Cook vegetables like broccoli, carrots and asparagus until they're about halfway done. "Then cover and take [the pan] off the burner. The vegetables will continue to steam for a few minutes," he explains.

Clark adds that the same method can be used with chicken or duck breasts, which can easily be overcooked. For boneless chicken breasts, for example, she gets the skillet hot over high heat. She adds butter and when it stops sizzling, she adds the chicken (skin-side down) and immediately turns the heat to low. When the chicken has turned a golden brown, she turns it over, turns off the heat and covers the pan. The residual heat in the pan cooks the breast the rest of the way.

In his restaurant, McBride times his steaks by pulling them off the grill and letting them rest for six to eight minutes before serving. Bigger cuts of meat need more resting time, he notes. "For big parties, where we make a huge roast like a prime rib, the rest time can be 25 minutes."

While the meat is resting, "you can make a sauce or saute some veggies to finish the meal," he suggests.

"All meats, whether grilled or roasted, benefit from a 10- to 20-minute rest at the end of cooking," advises Parsons. Clark follows the rule of 25 percent of the cooking time. "If you've cooked a roast for an hour, let it rest 15 to 20 minutes," she says.

And if you're just too hungry to wait that long? "It's like in life," she says. "Any resting time is better than none."

Bourbon-Marinated Flank Steak

(4 servings)

Talk about resting -- in this recipe, the marinade tastes better if you let it "rest" at least 30 minutes before using (you could even make it the day before), and flank steak should always rest for at least 5 minutes before it is sliced. The cook doesn't rest, however; while the flank steak is sitting for its prescribed 5 minutes, quickly broil some asparagus (recipe follows). Adapted from "Damon Lee Fowler's New Southern Kitchen" (Simon & Schuster, 2002).

1/2 cup bourbon

1/4 cup red wine vinegar

1 large or 2 small cloves garlic, minced

1/4 cup minced shallots or yellow onion (about 2 small shallots or 1/2 small onion)

1/2 ounce (about 2 tablespoons) dried mushrooms (don't bother reconstituting in water)

Pinch of freshly grated nutmeg

Salt and freshly ground black pepper to taste

Cayenne pepper to taste

1/2 cup peanut or canola oil

1 flank steak (about 13/4 pounds)

In a food processor or blender, process the bourbon, vinegar, garlic, shallots or onion, dried mushrooms, nutmeg and salt and black and cayenne peppers to taste until the shallots and mushrooms are finely chopped. With the motor running, slowly add the oil in a steady stream and process until the mixture is completely combined. Set aside to allow the flavors to meld for at least 30 minutes and up to 2 days.

Rinse the steak and pat dry with paper towels. Using a sharp knife, make crisscross slashes about 1 inch apart on both sides of the steak. Place the steak in a shallow glass baking pan. Pour over the marinade and turn the steak several times to coat. Cover and refrigerate for at least 1 hour and up to 8 hours.

Prepare a charcoal grill or preheat the broiler.

Drain the steak, discarding the marinade. Transfer the steak to the grill or a broiler pan and cook until the steak is nicely browned on 1 side, about 5 minutes. Turn and continue to cook until the steak is evenly browned and done to your liking, about 5 minutes more for medium. (Flank steak should never be broiled beyond medium or it will be tough.) Remove the steak and tent with foil; let it rest for at least 5 minutes. Transfer the steak to a cutting board and slice as thinly as possible, across the grain, at a 45-degree angle. Transfer the steak to a warm platter and serve immediately.

Per serving: 416 calories, 42 gm protein, 1 gm carbohydrates, 24 gm fat, 82 mg cholesterol, 8 gm saturated fat, 223 mg sodium, trace dietary fiber

Broiled Asparagus

(4 servings)

The 5-minute window while your steak settles down is the perfect time to make this simple, delicious asparagus. If you like, you can even pour the small amount of steak juices that collected in the bottom of the broiler pan over the asparagus before broiling. Or not. The asparagus will be good either way.

11/2 pounds fresh asparagus, trimmed

2 tablespoons olive oil

Salt and freshly ground black pepper to taste

Freshly squeezed lemon juice to taste (optional)

Preheat the broiler.

Place the asparagus in a single layer in a roasting pan and drizzle with the oil. Shake the pan slightly to coat the asparagus with oil. Season with salt and pepper to taste.

Broil the asparagus, turning the stalks once or twice to ensure even browning, until done, 5 to 8 minutes, depending on the thickness. Asparagus is done when the thickest part of the stalk is tender when pierced with a fork. Sprinkle with lemon juice, if desired, and serve immediately.

Per serving: 48 calories, 4 gm protein, 4 gm carbohydrates, 3 gm fat, 0 mg cholesterol, trace saturated fat, 75 mg sodium, 4 gm dietary fiber

Herbed Lamb Chops

(4 servings)

This crunchy topping of herbs, bread crumbs and mustard is a wonderful complement to lamb's assertive flavor. The chops need to rest for about 10 minutes before serving and, while they do, make the following sauteed zucchini dish. Adapted from "French Food at Home" by Laura Calder (William Morrow, 2003).

8 lamb chops (rib or loin)

Salt and freshly ground black pepper to taste

2 to 3 tablespoons olive oil, plus additional if needed

4 tablespoons bread crumbs

1 heaping tablespoon finely chopped fresh parsley

1 tablespoon mixed dried herbs, such as thyme and rosemary

2 teaspoons Dijon-style mustard

Preheat the oven to 450 degrees.

Pat the chops dry. Season the chops on both sides with salt and pepper to taste and rub with just enough oil to coat.

In a large skillet over medium-high heat, heat about 1 tablespoon of the oil. Add the chops, being careful not to crowd the skillet, and cook just until browned on both sides, about 1 minute per side. Transfer to a baking sheet; set aside.

In a bowl, combine the bread crumbs, parsley and dried herbs. Add the mustard and just enough oil (1 to 2 tablespoons, plus additional if needed) to bind the topping. Divide the topping into 8 portions and pat a portion on top of each chop.

Transfer the chops to the oven and roast until the topping is crisp and the meat has reached the desired degree of doneness, 8 to 10 minutes. Transfer the chops to a cutting board and let them rest for about 10 minutes before serving.

Per serving: 564 calories, 31 gm protein, 2 gm carbohydrates, 47 gm fat, 127 mg cholesterol, 19 gm saturated fat, 243 mg sodium, trace dietary fiber

Zucchini Saute

(4 servings)

When zucchini is sliced paper-thin and sauteed, it becomes meltingly soft with sweet, buttery ruffles in shades of green and cream. It's perfect as is, but you can add a sprinkling of fresh herbs if you want. Adapted from "French Food at Home" by Laura Calder (William Morrow, 2003).

2 pounds small zucchini, washed but not peeled, ends trimmed

2 tablespoons olive oil

2 to 3 tablespoons unsalted butter

Salt and freshly ground black pepper to taste

Using a very sharp knife or a mandoline, slice the zucchini crosswise into paper-thin rounds. Set aside.

In a large skillet over medium heat, heat the oil and butter. When the foam subsides, add the zucchini and cook, tossing occasionally, until the zucchini is wilted, ruffled and just beginning to brown, 10 to 15 minutes. Season with salt and pepper to taste and serve immediately.

Per serving: 88 calories, 3 gm protein, 7 gm carbohydrates, 7 gm fat, 8 mg cholesterol, 2 gm saturated fat, 77 mg sodium, 3 gm dietary fiber

Umbrian-Style Turkey Breast

(6 servings)

This Italian-inspired recipe is adapted from one for pork loin roast from "How to Read a French Fry" by Russ Parsons (Houghton Mifflin, 2001). Like pork loin, turkey is quite lean, so you will have to be very careful not to overcook it or the meat will be dry. An instant-read thermometer is crucial -- roast the turkey just until the temperature registers 155 degrees. As it rests, the temperature will rise to about 165 degrees, but the meat will remain moist. While the turkey is resting, make the following sauteed spinach recipe.

2 teaspoons coarsely ground black pepper

2 teaspoons fennel seeds

2 teaspoons kosher salt

33/4-pound bone-in turkey breast

2 tablespoons olive oil

Using a mortar and pestle, spice grinder or coffee mill, smash or process the pepper, fennel seeds and salt until finely ground. Set aside.

Rinse turkey with cold water, pat dry and place in pan. Rub the spice mixture evenly over the turkey, making sure to get as much seasoning as possible under the skin so that the meat is seasoned as well. Drizzle the oil over the turkey and gently rub to evenly coat with oil and to push the spices into the meat. Marinate for 1 hour at room temperature or cover loosely and refrigerate for 2 hours.

Preheat the oven to 325 degrees. Have ready a roasting pan fit with a wire rack.

Transfer the turkey to the rack and roast, until the interior temperature reaches about 160 degrees, about 55 minutes. (Federal guidelines call for a final internal temperature of 170 for turkey breast. To test for doneness, check the roast in several places with an instant-read thermometer, being careful not to touch the bone with the tip of the thermometer.)

Remove the turkey from the oven, tent with aluminum foil, and let it rest for 20 to 30 minutes, which will allow the temperature to continue to rise.

To serve, carve the turkey into thin slices and pile onto a platter or individual plates. Spoon over any juices from the roasting pan.

Per serving: 403 calories, 36 gm protein, 1 gm carbohydrates, 27 gm fat, 120 mg cholesterol, 9 gm saturated fat, 496 mg sodium, 1 gm dietary fiber

Sauteed Spinach

(4 servings)

Fresh spinach is an easy side dish because it cooks so quickly. Here it gets a classic Italian turn -- sauteed until tender and then quickly bathed in garlicky olive oil. Adapted from "The Classic Italian Cookbook" by Marcella Hazan (Knopf, 1976).

2 pounds fresh spinach (about 2 bunches) or four 5-ounce bags of fresh baby spinach or two 10-ounce packages frozen spinach

Salt to taste

2 cloves garlic, peeled but left whole

1/4 cup olive oil

If using bunches of mature spinach, trim off thick stems. Wash spinach in cold water to remove all traces of dirt. Shake to remove excess water (it's not necessary for the leaves to be completely dry).

Cook spinach in a covered pan over medium heat with a pinch of salt and no more water than what clings to the leaves after washing. Cook until tender, about 10 minutes.

Drain well, but do not squeeze. (If using frozen spinach, simply cook thawed spinach with pinch of salt in a covered pan for 11/2 minutes; drain.)

In a skillet over medium-high heat, saute the garlic in oil. When the garlic is well browned, remove and discard the cloves and add the drained, cooked spinach and 1/2 teaspoon salt. Saute 2 minutes, turning frequently. Taste and correct for salt. Serve hot.

Per serving: 143 calories, 6 gm protein, 1 gm carbohydrates, 14 gm fat, 0 mg cholesterol, 0 gm saturated fat, 339 mg sodium, 19 gm dietary fiber