It was an inspired gamble. Julie Powell, then a low-level government employee in her late 20s and looking, as she put it, “to pull myself out of a tailspin of secretarial ennui,” embarked on a quest to follow all 524 recipes detailed in Julia Child’s epic 1961 cookbook, Mastering the Art of French Cooking, in the span of a single year. Powell chronicled her experiences in a candid, sharply written blog, and a culinary star was born.

Now, perhaps inevitably, comesJulie & Julia, a Nora Ephron comedy inspired by two memoirs: Powell’s book-length expansion of her popular blog, from which the movie takes its name, and My Life in France, Child’s account of her longtime love affair with the French, their exquisitely rich food and her husband Paul, whose great-nephew Alex Prud’homme helped her complete the book before her death in August 2004.

The movie’s masterstroke, which will surely be recognized come awards season, is the casting of Meryl Streep as Child. By now, we’ve come to expect dead-on performances from Streep, and she doesn’t disappoint here. As Child, whose passion for food inspired her to become a chef and later the most recognizable culinary figure in America, she is lively and endearing, playful yet forceful when need be. Child rose to fame in large part because of her irrepressible, larger-than-life personality, and Streep captures all her quirks, from her oddly tremulous voice to her joyously expressive physical tics.

Julie & Julia follows Child and her doting husband (Stanley Tucci, always in fine form) from the late ’40s, when her need for a hobby leads her to the famous Le Cordon Bleu cooking academy in Paris, to the publication of her now-legendary cookbook. Life isn’t always easy – Paul’s job with the State Department necessitates several relocations – but you’d never know it from watching Child, who, even at her lowest, seems plucky enough for the two of them. She’s a force of nature, and one rightly suspects that those standing in her way, be they nay-saying publishers or the McCarthyites who question Paul’s patriotism, will soon be tossed to the wayside.

Child’s background is fascinating – long before becoming an award-winning TV personality, she served in World War II researching secret intelligence, meeting her future husband while stationed in Sri Lanka – and could make a movie all its own. Yet Julie & Julia dutifully splits time between her story and Powell’s, which is set mostly in a tiny Brooklyn apartment above a pizza parlor.

It is there that Powell (Amy Adams) and her exceedingly patient husband Eric (Chris Messina, of Vicky Cristina Barcelona) lead a cramped but otherwise happy existence – happy for Eric, at least. Powell spends her days dealing with agitated 9/11 survivors on a government hotline; by night, she’s glued to the stove, wrestling with Child’s recipes, then rushing to the computer to document the experience.

It’s not a thankless role for Adams, as some critics have alleged, but Powell, in the movie as in life, never steps out from behind her idol’s shadow. Unlike Child, who seems buoyed by an unsinkable cheeriness, Powell is stuck in a single mode: frantic. Adams disappears into the role admirably – she’s a jittery bundle of exposed nerves – but Powell’s story is the less arresting of the two. Her hard-won triumph comes in the form of a book deal (no surprise there), but like so much of her time in Julie & Julia, Powell’s journey feels like a diversion.

The movie is sweet, amusing and, unlike one of Child’s decadent platters of beef bourguignon, mostly weightless; if not for Streep’s expert portrayal, which could have turned to parody but is instead both boundlessly energetic and respectful, it might float off the screen. One senses that Powell’s work was not particularly suited to film.

In that regard, Julie & Julia recalls another Streep vehicle: 2002’s Adaptation, in which director Spike Jonze and writer Charlie Kaufman used Susan Orlean’s The Orchid Thief as the starting point for a surreal, highly fictionalized account of one screenwriter’s attempt to adapt the unadaptable. Here, Ephron plays it straight, and while she succeeds in establishing parallels between the lives of her heroines, those parallels seem more superficial than compelling.

In fact, the two title characters seem only tenuously connected. For Child, cooking is a labor of love, born of a stubborn desire to bring the joys of French cuisine to American kitchens; for Powell, it is an unhealthy obsession, a narcissistic quest to achieve the eminence she perceives as her destiny. She adopts Child as both an imaginary friend and guardian angel; in Powell’s mind, her mentor can do no wrong, even after she learns that the formidable Julia regards her work with little more than sidelong contempt.

Julie & Julia never tries to explain this inconvenient truth – clearly, there will be no tearful meeting of master and apprentice in the movie’s waning moments – but here the two women are, paired together for posterity anyway. Bon appétit.