Frederica von Stade has sung Cinderella in Jules Massenet's "Cendrillon" dozens of times, but it will be different tonight. When the curtain goes up on the Washington Opera's newest presentation, the audience will include her two daughters, Jenny, 10, and Lisa, 7, flown down from their home on Long Island for the occasion.

"I had to lure them down with all kinds of tales," von Stade says. "They said they wouldn't understand it and I told them, 'You can read what's being said, and there's the glass slipper and pretty costumes and the coach and the ballet.' Mommy's singing doesn't do it. They're always shutting me up in church, saying, 'Please, Mommy, don't sing. Everybody turns around and stares at us.' "

"The girls have seen me singing the other Cinderella, Rossini's 'Cenerentola,' and I think Jenny may have seen 'Cendrillon' the last time I sang it seven years ago," she reflects. "But she was too small to remember anything; she must have been about 2. I was expecting Lisa at the time; now, my Prince Charming {mezzo-soprano Susanne Mentzer} is pregnant. This is a very fertile opera."

A pregnant Prince Charming? That's the sort of thing that can happen in opera, where women with relatively low voices are often given trouser roles. Von Stade, who like most mezzo-sopranos is fairly lithe and slender, frequently takes such male roles written for women as Hansel in "Hansel and Gretel," Cherubino in "The Marriage of Figaro" and Octavian in "Der Rosenkavalier." Her Hansel (which can be seen in the videotape and LaserDisc editions of the Metropolitan Opera production) is a model of prepubescent machismo and roughneck energy -- remarkable for a woman who made her Metropolitan Opera debut (starting at the top) in 1970 and will be 43 June 1.

"Singing the part of a little boy doesn't bother me," she says. "Even at my advanced age, I get a kick out of doing Hansel. I'm repeating it, not next year but the year after, and I do love doing it. Hansel forever! Even when all my teeth fall out."

But with "Cendrillon" and with Debussy's "Melisande," which she did recently at the Met, she is glad to be wearing dresses again: "People ask me if I'm having a good time singing Cinderella and I say, 'Am I ever!' because I've been doing pants roles for a year, and now I have two girls in a row, Melisande and Cendrillon -- what could be nicer? And with pretty party dresses and ball gowns and glass slippers and long hair -- oh, it couldn't be more fun."

Von Stade is sitting in her dressing room backstage at the Kennedy Center Opera House -- a starkly functional room for an art that, for all its sometime glamor, requires hard work, highly specialized skills and no-nonsense attitudes offstage. Unshaded light bulbs project from the room's bare walls; there are lots of mirrors, a wash basin. Gauzy floor-length party dresses hang in a corner, hinting at the magic and illusion it will be von Stade's job to create. But they hang from a rack that looks like a bit of surplus plumbing.

There is one unexpected spot of color: a basket of grapes on a corner of the dressing table. They are a gift, von Stade says, from "one of the world's nicest and most capable backstage crews ...

"They asked me, 'Do you like anything special backstage?' " she recalls, "and I said, 'Oh, I love caviar, but if you can't give me caviar, a grape or two would be nice ...' And I've had fresh grapes here every night. I told them, 'Don't you do it anymore; it's too much trouble and I was just teasing.' But there they are."

Washington has a special meaning for Frederica von Stade. Though she was born in New Jersey and has made much of her career in New York and Europe, this is the city where she lived during her formative years, the city where the idea of being an opera singer first began to germinate deep in her unconscious. It is also the city where, as a self-described "street kid," she first learned to swagger like Hansel.

"My father died near the end of World War II, a couple of months before I was born," she says. "I did a lot of my growing up in Washington while my mother worked for the government. I went to Holy Trinity parochial school in Georgetown and then I went to Stone Ridge Convent of the Sacred Heart near the naval hospital in Bethesda. In fact, I drove out there the other day and got all nostalgic because I was {her voice moves up an octave} a little girl there.

"I knew Georgetown as a kid. All the area down along the water used to be old dumps, and my brother and I would go down there and jump on the old tires. When I think back on it, we were really street kids. We lived at 33rd and Volta, and now it's all chic, but then it wasn't as fancy as it is now."

The Washington Opera was one of the first companies to recognize von Stade's abilities, casting her in "Il Ritorno d'Ulisse" in the 1974-75 season. These connections with the city and the company are part of what brings her back now that she is one of the world's most sought-after singers. But Jenny and Lisa are the two principal reasons why she is singing more in the United States these days and less in Europe. She has been turning down invitations from such places as La Scala and Salzburg to spend more time at home with her children.

Although she performs in all the operatic languages, von Stade has a special affinity for the French repertoire, dating back to when she was 18 and went to live for a year in Paris. "I did that," she explains, "instead of going right to college after high school. I had no interest. My grandfather said, 'I'm going to give you some money when you're 18; you can't buy anything with it -- no clothes, no car; you have to do something with it.' So I decided to go and live in France. I worked as a part-time nanny, a waitress, all kinds of jobs. I just loved Paris, and I learned the language.

"French music is luscious ... Even when the French are vulgar it's not really vulgar. In an opera like 'Mignon' or 'Cendrillon,' there are moments so silly that if you put them on TV today people would throw spitballs at the television set. But with the music, eventually they convince you. The French have a sense about proportion, and they know what works."

Of the two Cinderella operas she sings, von Stade thinks the one her daughters will see tonight is the one they will find most recognizable. But she herself loves them both.

"They're so completely different ... they're worlds apart. I love singing 'Cenerentola'; there's something about it that feels so good in the voice, and I really believe so much in bel canto and particularly Rossini's music. It does everything that can be accomplished through the voice.

"And yet every little girl has a Cinderella dream, I think, and this opera is closer to the fairy tale. It's a wonderful opera, and the way Brian Macdonald directs it and Mario Bernardi conducts it is just terrific. It's the same team that we had 10 years ago, and Mario is just perfection with this music. He is 100 percent respectful of everything that Massenet wrote. And Massenet wrote everything down: 'not too slow here, but move along; rallentir {slow down} only at the last minute,' so that it doesn't move into a sort of soupy sweetness."

Her own childhood acquaintance with Cinderella, outside of storybooks, centered on Walt Disney's animated treatment. "Oh, Walt Disney!" she says in a voice that still rings with a child's excitement. "I saw it again this year, because, you know, it was her anniversary ... 'Cinderelly, Cinderelly, night and day it's Cinderelly ..." she begins singing the song of the friendly mice from the movie -- perhaps the best voice that has ever sung those lyrics.

She's begun to realize, she says, "that I really started performing at about 6 or 7. Through the convent and my very Catholic upbringing, I participated in a lot of music, a lot of theater, processions ... I remember my first communion at Stone Ridge, the light flooding in through the windows, the girls in lovely dresses ... an intensely beautiful scene. I can remember my mother giving me red roses when I was in a play, and I remember the encouragement of my family and the nuns. I didn't realize I wanted to be a professional performer until I was in my twenties. Or rather, I pretended I didn't want it, because it was so important I could not bear the thought of trying and failing.

"Then, little by little, I won competitions and took singing lessons; I auditioned at the Met and they gave me small parts and gradually the parts got bigger. But all through the first 10 years of my career, I had the feeling: 'Someone will find out I can't do this, and my career will end.' "

Now that she is ranked among the world's top mezzos, rivaled only by Tatiana Troyanos and perhaps Marilyn Horne, "I'm beginning to realize I can do it and it is a permanent reality. I'm very lucky and enormously grateful for all who contributed. There is a whole army of them: friends, critics, my teachers, my family, all the people who egg you on when you're not sure you can do it."