MOVIES : Fresh Princess : In a town full of wanna-bes, Alicia Silverstone has stormed the teen limelight. Who’d guess behind that bubblegum facade lies an accomplished comedian?

Alicia Silverstone is recovering from the flu. She asks to meet at the Four Seasons Hotel at Beverly Hills so she can have her favorite chicken soup. Obviously subscribing to the “feed-a-cold” axiom, she also orders, and inhales, a bowl of tomato soup, warm scallop salad, bread lathered in butter, sorbet and, to top it off, the interviewer’s uneaten avocado.

If you are what you eat, Silverstone is no Hollywood starlet grazer. She is a growing girl with a healthy appetite.

And like almost everything else about her, Silverstone’s eating habits veer from typically teen-age to individual and idiosyncratic. That also includes her opinions on acting, sex, religion and even Shakespeare.

Early in the interview, her publicist appears at the table to mother-hen her. She needn’t have worried. True, on screen Silverstone taps into the latent Humbert Humbert in all of us, a vein that was mined in 1993’s “The Crush,” in which she played a homicidal teen-age temptress. Through the camera’s eye she was all peaches and cream with pouty asymmetrical lips.

But in person she brings out one’s protective older-brother side. It’s annoying even if the waiter tries to talk to her for too long. The precocious, glossy glamour she projects in Aerosmith videos like “Cryin’ ” and in her new comedy, “Clueless,” has very little spillover into her real life--the Four Seasons dining room notwithstanding.

She wears her hair loose, a simple white undershirt and no makeup, looking younger than her 18 years. Even if she sometimes sounds grounded and mature beyond her years, in the next breath she’ll say something decidedly wide-eyed and not be the slightest bit embarrassed about it.

“It’s shocking,” says “Clueless” director-writer Amy Heckerling. “After spending months with her as the character, then I see her again, and I realize she’s not Cher [Silverstone’s character in the film] at all. She’s Alicia, a little girl. She’s very happy with her dog [Samson] and wearing sweat pants. And then she’ll get all glammed up and go to work.”

Though she lives in Los Angeles, Silverstone is rarely on the photo-op circuit like some of her (slightly older) fellow actors, such as Drew Barrymore or Leonardo DiCaprio. What little socializing she does is with her two or three best girlfriends--usually at home. She’s spent most of the morning grocery shopping with actress Jennifer Rubin, with whom she starred in “The Crush.” Rubin has just moved into Silverstone’s Hollywood Hills bungalow.

“Going shopping together for the first time makes us official roommates,” she says with a cheerful smile. “It sounds silly and simple, but if I didn’t have a roommate, I’d have no one to cook or stay up late with.”

Many rising actresses are single-minded. Silverstone is no exception. But her focus is more like that of an athlete. “There’s so much out there to do, and I can’t do it all at once. But I want to do it so much.”

Aware that Hollywood isn’t exactly overflowing with challenging roles for teen-agers, she’ll take on any role that strikes her as “meaty,” she says--or at least gives her the opportunity to work with and observe interesting actors.

“It’s all what you make of the roles. I feel all the choices I’ve made have been the perfect ones at the time,” she says.

Even if a film doesn’t turn out well or advance her career--as has been the case with such recent efforts as the Dean Koontz adaptation “Hideaway,” starring Jeff Goldblum, and “True Crime,” which may go straight to video--learning through experience is what counts most for her at this point.

So Silverstone can afford to rack up the calories. She burns ‘em. She has made five films in a row and spent June at the Shakespeare Company in Massachusetts, which she describes as a Bardian boot camp. “I didn’t know anything about Shakespeare, except that I’ve always loved it,” she explains. “We had this intensive training from 7 a.m. to 11 at night, six days a week. We learned a lot about voice, movement and text.”

She took a role in Alain Corneau’s French period romance “Les Nouveaux Mondes” mainly for the opportunity to see Paris, she admits. She was bowled over by working in France. “It was so much classier. Even the drivers wore a suit and tie. And you only worked nine hours a day with a whole hour for a sit-down lunch. It was so old-fashioned Hollywood.”

It’s delightful to discover that the only thing she didn’t enjoy about Paris was the food. “I grew up in an English household and the food in France is too spicy and rich,” she frowns. “I lived on oysters and new potatoes mashed with butter.”

Like Cher in “Clueless” (she and her best girlfriend were both named after famous singers who now do infomercials, her character explains in the film), Silverstone is from an upper-middle-class background. Her British-born parents raised her in the tony Northern California suburb of Hillsborough with summers in England. Though she’s lived on her own since she was 15, she keeps in contact with her mom and dad, who are in England for the summer.

“I grew up with girls like Cher around me, shallow, materialistic,” she says. “When I first read the script, I didn’t like her. Even though I knew I had the part, it sat there for three months. I didn’t want to work on it.”

And yet, she has made Cher appealing and disarming, in spite of her solipsism. She did it, she says, by unearthing the character’s good traits. “What I identified with in Cher was her compassion for her friends and her relationship with her father. She was just lovable. Not that I know any girls like that. Most of those girls are not very happy.”

If it all sounds like teen fluff, think again. Heckerling, who made the definitive teen movie of the ‘80s, “Fast Times at Ridgemont High,” has constructed a comedy of manners in “Clueless,” resetting Jane Austen’s “Emma” in 1990s Beverly Hills. It may look like “90210,” but it plays up to its audience, not down.

“I think Amy wrote this much more for her friends. I don’t know how many kids will get the fact that Billie Holiday was a girl,” says Silverstone, about one of Cher’s more endearing faux pas in the film. “But what I like about the movie is that it treats kids like they’re smart. It takes them seriously.”

Like many older, more experienced actresses--Michelle Pfeiffer and Meg Ryan come to mind--Silverstone pinpointed the film’s comedic tone by deliberately ignoring it. “I’m not, myself, funny,” she says. “So I didn’t think I could do comedy. It all came out of being with Cher, believing it was all so serious to her. She’s so committed to who she is. It was all there in the writing.”

Maybe it was on the page, but Heckerling says it was definitely Silverstone who brought it to the stage. “She got the jokes. She understands the humor in people. And she understood that what’s funny about Cher is that she’s so naive and trying to be so sophisticated.”

While Cher’s contemporaries indulge in drugs and sex and booze--the story is, after all, about Beverly Hills children of privilege--her only vice is shopping. Surprisingly, Cher is, and admits to being, a virgin. Silverstone shrugs, “Everyone knows Cher is popular and cool. And she’s a virgin. And so what? It’s not that she isn’t open to sex or drugs. And she doesn’t judge you if you do or don’t. She’s just doesn’t indulge.”

Otherwise, when it comes to the subject of sex, Silverstone keeps her own counsel. After being elevated to babedom via Aerosmith, she is acutely aware (and if she isn’t, her publicist is) that she is potential bait for the tabloid sharks.

“I live a very normal life,” she says. “But what concerns me is that the difference between what I do and what you do is that what I do will be in the papers.”

Then with a wave of the hand she dismisses it all. “I’m not a celebrity. I’m an actress. If I worry too much about my image, then I become a celebrity.”

She is much more open about the subject of spirituality--except for her noncommittal answer about the Forum, a self-improvement organization in which she has participated. “It was just a great thing to do,” she responds curtly.

Here her publicist interrupts to explain Silverstone’s reticence, explaining that she fears the media will blow it up into a “cult thing.”

But again, Silverstone’s approach to spirituality turns out to be much more catholic than that. She has, in the past, spoken proudly of her bat mitzvah at age 13, even if she’s still not quite convinced of the existence of God: “I try not to think too much about religion or intellectualize it, because what is spiritual is not what’s in the brain. It’s what’s inside. I just try to be a good, honest human being and let it be with me.”

For the first time in the past three years, Silverstone is without a new assignment--another new experience for her. She alternates between wondering whether she should be working and not wanting to work unless she has to. “Maybe I’ll just read a lot and grow that way. I feel lucky that I’m young. So I have some time. I think.”