Nora Ephron’s silly, charming Julie & Julia demands that viewers accept and enjoy a generous sprinkling of Hollywood pixie dust to really appreciate her film. To belabor the inevitable food metaphors, it is a delicious, escapist confection best savored in the moment, with no expectation that it will sustain you in the days ahead.

Ephron’s film is about the intersection of two lives: that of real-life Julie Powell, an unknown Queens blogger who decided to chronicle her efforts to cook her way through all 524 recipes in master chef Julia Child’s Mastering the Art of French Cooking and that of Child herself, who appears in a parallel storyline.

Adrift in an aggressively careerist Manhattan, Julie (Amy Adams) decides that blogging is a way to make her mark. Working as a telephone operator at the post-Sept. 11 Lower Manhattan Development Corporation, Powell feels like a loser. She’s a failed novelist left in the dust by her hyper-competitive female friends who can barely break away from their Blackberries to acknowledge her presence.

While blogging may be a uniquely 21st century phenomenon, Powell’s anxiety over never finding her purpose in life isn’t. Decades earlier, in 1940s Paris, Julia Child is shown suffering from the same existential crisis: she is a woman of a certain age with no real vocation or passion. It’s hard, at times, to feel sorry for Child. Paris, in Ephron’s hands, often looks like fanciful Amélie Gallic porn. Ivy crawls artfully over the wrought iron Juliet balcony in the elegant apartment where Julia and her diplomat husband Paul (Stanley Tucci) cook and canoodle. And a golden light hangs on every scene at Le Cordon Bleu, the all-male cooking institution where her feminine presence is not always appreciated, but where she discovers her destiny.

Julie & Julia centers on Powell and Child’s shared experience of finding self-worth and happiness in carving out an area of expertise. Ephron, a longtime foodie herself, also shows the magic of creativity — be it filmmaking or cooking — in connecting people across time and space. But the strategy of cutting back and forth between Julie and Julia begins to take its toll in the entertainment department.

As a personality, Julie Powell just can’t hold a candle to Julia Child, that animated, deliciously idiosyncratic force of nature who manages to combine both ease and expertise in the kitchen with a lovable, bumbling quality hilariously lampooned by Dan Aykroyd on Saturday Night Live (a clip Ephron gamely includes). Streep is a force to be reckoned with, a planet whose gravitational pull renders all lesser satellites space dust. In Julie & Julia, Streep pulls back from the edge of camp (but often just barely) to celebrate Child’s goofiness but also her all-American optimism and trace of sadness in being a misfit who frets and pines before finding her niche. Streep plays the role with gusto, shrieking orgasmically over her first taste of the dish that single-handedly convinced her of the superiority of French cooking: sole meunière. “Butter,” she whispers, with lascivious relish.

The orgasms apparently extended to the Child bedroom. The most delectable love story in Julie & Julia is not the one between Child and French cuisine, but the one between Child and her adoring husband — an absolutely delightful Stanley Tucci. It is the lusty, laughing union of two sensualists who scoop up life’s pleasures by the handful. The frank, bawdy depiction of this loving marriage of two ordinary-looking but besotted people is more subversive than all of the bared breasts and sex-talk dominating cinema screens.

Amy Adams has her work cut out for her. As shiny as a new penny, Adams does poorly with misery, looking about as downtrodden as a girl scout on a slow cookie sale day. And the scene where Powell — deep into all of those butter, cream and fat-laden French dishes — begins to fret about gaining weight is ludicrous. Who does Ephron think she’s kidding? It is irritating to see Adams’ chirpy lack of transformation (you couldn’t pinch an inch of excess flesh on her frame) next to Streep’s willingness to be oafish and goofy and less than attractive.

But the biggest hurdle in Julie & Julia, the one that makes you feel slightly miffed each time Ephron cuts away from Child and Paris to Powell slaving over a beef bourguignon in her Queens walk up, is how pitifully the present compares, at least in Ephron’s hands, to the gloriously romantic, zestful, artful past. If you harbor even the slightest cynicism about modern times, you will be hopelessly besotted by the Child scenes where anxiety and self-doubt were allowed, but not to the point of relentless navel-gazing and epic self-absorption. Julie & Julia offers a generational compare and contrast between a postwar era when people lived instead of blogged and our own detached, virtual, meta-existence.

The original gangsta foodie, Child lived in a time before food culture became annoyingly ever-present and in an age when lived experiences trumped parasitic, analytical ones. Child not only lived food, she looked the part: a woman of substance and physical impact. Powell is thin not just in body, but in character, and every time Ephron jumps back to Queens, your heart sinks a little.