WHEN THE WHO played at the Capital Centre this September, lead vocalist Roger Daltrey requested that a quarter-pint of Haagen-Dazs ice cream be placed on stage every 20 minutes.

Vanilla.

In a china bowl.

With a silver spoon.

Mick Jagger may preach that "you can't always get what you want," but whether it's before, after or during a performance, the rock stars who perform at the Capital Centre do get what they want--to eat, that is. What, when and how the band and crew are to be fed are determined through "riders" (clauses in the performance contract) that are written by the star's agent and sent to each city's promotion company.

In Washington, the American Cafe caters Cellar Door Productions' performances at the Capital Centre, lugging half-prepared food such as prestuffed raspberry chicken or escargots from Georgetown to Landover. The catering van carries convection and microwave ovens for heating dishes, and hot plates for boiling water if the request is lobster.

The Bullets' cinder block locker room is turned into a palatable dining setting, often with linen tablecloths and silver, when stars come to town. "We air it out," said Vickie Hix, the American Cafe's market manager, who is in charge of the transformance. Besides catering to the demands of the performers, the American Cafe has to contend with traffic jams (once its van was waylaid in traffic for so long that the deliverers had to slice meat on New York Avenue); road crews that at first think they're groupies, not caterers ("we try to dress conservatively," said Hix); logistical problems resulting from the Capital Centre's remote location (during Van Halen's performance, for instance, the catering staff had to resort to a nearby supermarket for hors d'oeuvres refills); and unexpected cravings from band members (a baked potato had to be rustled up on one occasion from a local restaurant).

A lot of the stars appear to be on diets, said Jason Wesley, catering director of the American Cafe, and there are numerous vegetarians among both crew and bands. Oranges for juice are a popular request too, as many of the groups travel with their own juicers. While healthy-sounding foods like yogurt and mineral water are often included in the rider, "instant sugars"--foods such as candy bars and cookies--go alongside for quick energy before the show. Ozzy Osbourne's rider even requests "1 large jar glucose." And on stage, honey, lemons and Gatorade are staples.

Requirements for crew members are quite different: hearty meals such as turkey, gravy and mashed potatoes rather than extravagances. Frequently, though, stagehands are invited to finish off dressing-room leftovers.

While the American Cafe caters the food, John "Chief" Gentry, production director of the Capital Centre, is in charge of providing alcohol, the use of which he said is "not as bad as it used to be." Nonetheless, Gentry says bands "have expensive tastes" when it comes to alcohol, with Jack Daniels Black Label leading the list. Courvoisier cognac is another favorite, he says, and Heineken heads the beer requests. Specifics are not ignored; the Greg Kihn Band listed "3 bottles Beaulieu Vineyards Cabernet Sauvignon" (no year, though). The same attention to detail is given to other beverages; Pat Benatar's rider called for A & W Sugarless diet soda and Lipton's Lemon Lift tea.

Some rock food excerpts from this year's Cap Centre concerts:

The Who--Besides the ice cream, Daltrey requested sashimi be brought backstage after every performance. "It really boosts up his energy after the show to have Japanese food," said Anne Weldon, U.S. representative for The Who. Wesley says she bought it from Sushi-Ko restaurant on Wisconsin Avenue, hiring a special driver to deliver it right after the show so that the fish would still be fresh.

Linda Ronstadt--Before the singer came to town, a copy of "The Pritikin Program for Diet and Exercise" was sent to the American Cafe caterers with instructions to prepare a presound-check dinner for Ronstadt using recipes from the book. It's "more of a health thing than a diet thing" for Ronstadt, says Ira Koslow, vice president of Peter Asher Management, the star's personal management company. It's her way of "ensuring a healthy, diverse diet" while on the road, he adds.

Van Halen--A notorious candy obsession is the hallmark of this hard-rock group. Under the category of "Munchies," the rider reads: "M & M's (Warning: Absolutely No Brown Ones)." Hix of the American Cafe said she picked them out, to the amusement of watching band members. ( She shared them with the security staff.) Caterers are sure to take this clause seriously; finding some "brown ones" at a Midwestern concert led the group to trash the stage and dressing room.

Rush--"Rush Catering Supplement," the cover sheet reads for this band's food rider. The list of hors d'oeuvres for the 10:30 p.m. dressing room is lengthy and extravagant: "scampi shrimps and sauce, baked clams, smoked salmon, cream cheese and bagels, sushi, oysters on the half shell, escargots, fondue, king crabs and sauce and swedish meatballs." According to Wesley, Rush's road manager, Cellar Door Productions and the American Cafe worked out the logistics in a phone call--a procedure that is not uncommon for finalizing menus. Wesley said the group ended up with, among other items, kielbasa in puff pastry, escargots with extra garlic, smoked eye of round with french bread and mustard, crab claws, spiced shrimp and spinach salad.

Rush members are also partial to Bordeaux wine, according to Cindy Wallace of Cellar Door Productions. The specification wasn't in the rider, but Wallace says she went to Eagle Wine and Cheese and bought the group six bottles of the wine. Russ Everett of the shop reported that Chateaux LaTour, Petrus and Gruaud Larose were among them. Total sale: about $400.

Rush is also concerned about dining ambiance: "Please provide a living room suite (couch and chair, occasional chairs, coffee and end tables, carpet, incandescent lamps) and banquet tables with tablecloths," reads the rider.

Billy Joel--Dining atmosphere appears to be important in Joel's case too: "All serving areas must be covered by white linen and arranged in first class manner with silverware, glasses, cups, saucers, etc."

Rolling Stones--For $25,000 and three nights of eating, Baltimore's Pimlico Hotel catered a veritable backstage "affair" for the group during its Washington stopover in December 1981. Three food tents were erected behind the stage (two for the crew, the other for Stones and friends), and each night the band's tent had a food theme. The concert promoters wanted to "put on a show" for the Stones, said Charles Levine, the hotel's catering director. It certainly appears so.

For Seafood Extravaganza Night, for instance, the Stones' tent was equipped with raw bar, saute'ed mussels, Maryland crab cakes, Belgian endive salad and cold poached salmon with cucumber sauce. The next night, titled Marketplace, resembled a Lower East Side street scene, with bagels, hanging salamis, whitefish, deli meats, pickles, chopped liver and kugel. Except, that is, for the wine bar and ice sculpture in the shape of a tongue (the Stones' logo). The final night of backstage eating, dubbed American Cuisine evening, included scallops vinaigrette, steak tartare, escargots, potato skins with sour cream and caviar, baby rack of lamb, Szechuan chicken with peanuts and duck a l'orange.

Rod Stewart--Among the beverages requested in the dressing room by 7 p.m. for Stewart, group and friends: "2 qts. Courvoisier cognac, 2 bottles good port, 6 qts. hot sake, 1 qt. Stolichnaya vodka, 3 gallons fresh iced spring water." Besides instructions that "meals are to be served on hot chafing trays," that "plastic forks, paper plates are not acceptable" and the evening meal "should not consist of "take-out convenience-type foods," another clause reads: "It is the quality not the excessive quantity that is requested for Rod Stewart's dressing room."

Journey--Agents may not always be food mavens. In Journey's case, the American Cafe's Wesley said she talked the road manager out of the rider's request for one gallon of "shrimp and scallop casserole in cream garlic sauce." Scampi and oriental shrimp were the replacements.

Grateful Dead--The group travels with its own caterer.

Kenny Rogers--Favorite foods are apparent in an addendum that reads, "Note: If fresh seafood is available, please furnish double portions." The same goes for unfavorite foods: "Please do not use hot mustard."

Outlaws--Allergies or just plain distaste? "No shrimp or anything containing shrimp" reads this rider.

Squeeze--Cutting styles may also be specified; here it was "slabs not slices various imported cheeses."

Heart--Wesley said most of Heart's food was bought from Yes! natural food store. The natural food list goes on and on: "1 qt. grapefruit juice; 1 qt. apple juice; 1 qt. cranberry juice; 2 gallons Mountain Spring water; 3 6-packs Hansen's Natural Soda (in bottles if possible), lemon-lime, grapefruit and mandarin lime; 1 gallon 2 percent milk; 6 Yoplait yogurts; fresh lettuce, spinach or caesar salad with Hain (no preservatives) Natural Italian, buttermilk, blue cheese dressing; organic salted and unsalted nuts; assortment of organic (no preservatives) potato chips, corn chips and tortilla chips; Hain mayonnaise (No Miracle Whip!); small tray of cold fried chicken, thighs, breasts, legs and wings (no Colonel Sanders please)." The rider also requests a bouquet of fresh-cut flowers in a vase for the dressing room.

Ozzy Osbourne--One might think that Osbourne, having once bitten off the head of a bat during a performance, would have unusual food requests. But his group's rider was routine, and in one respect downright conservative: "No beer or alcohol is to be placed in any dressing room that is being utilized in conjunction with any aspect of the Ozzy Osbourne production."