Based on the book of the same name by Julie Powell and "My Life in France" by Julia Child and Alex Prud'homme, "Julie & Julia" segues back and forth between the past and the near-present, between a depiction of Julia Child's struggles to turn her love for cooking into a career and the life-altering impact she ultimately has decades later on one underappreciated cubicle worker living above a pizza shop in Queens, NY. The alternating storylines are slight and conflict is severely lacking, so the film, adapted for the screen and directed by Nora Ephron (2005's "Bewitched"), lives or dies based on the strength of the two lead actresses. Fortunately, Meryl Streep and Amy Adams (reteaming after their Oscar-nominated roles in 2008's "Doubt") are extraordinary here, lifting so-so material into an enjoyable, easy-breezy, late-summer trifle.

When husband Paul's (Stanley Tucci) job with the United States Foreign Service moves them to France in 1949, Julia Child (Meryl Streep) decides it best to fill up her days by learning a new trade. One of her great loves is food, and so her entrance into the Le Cordon Bleu cooking school seems like a natural fit. Despite a language barrier, Julia rises to the top of the ranks among her classmates and teams with fellow female chefs Simone 'Simca' Beck (Linda Emond) and Louisette Bertholle (Helen Carey) to teach a private cooking class of their own. When Simca and Louisette invite Julia to co-write a book with them on French cuisine, she is beyond thrilled. What starts as a fairly simple writing project, however, soon turns into a 700-plus-page tome that, despite being brilliant, turns off the publishing community. With nothing quite going her way and their move back to the U.S. imminent, Julia is left to wonder what her future holds.

Meanwhile, in 2002 Queens, aspiring writer Julie Powell (Amy Adams) works an unsatisfying office job at a development corporation and is getting cold feet about her impending thirtieth birthday. Yearning to finally finish something that she endeavors to begin, husband Eric (Chris Messina) suggests she start a blog. Sounds easy enough, but on what? Julie, who tends to relax after a stressful day by cooking, comes up with a daunting, even crazy plan—spend the next 365 days working her way through all 524 recipes featured in Julia Child's "The Art of Mastering French Cooking." As the blog takes off and Julie's dedication leads to pressure, frustration and self-fulfillment, her newfound hobby-cum-mission begins to put a strain on her marriage.

"Julie & Julia" isn't always seamless in its timeline shifts or in the telling of two separate sets of characters whose lives never intersect. Both sections are diverting in their own way, but neither one would be quite strong enough to stand on its own. Meryl Streep avoids doing a cheap imitation of Julia Child and instead, for two hours, becomes her. From her pronounced voice to her towering height to her effervescence of heart and soul, Streep has captured with enlivening shades the full embodiment of Child. The love she shares with husband Paul, earnestly played by Stanley Tucci (2008's "Swing Vote"), and her passion for food are two constants never far from the forefront of her scenes. Writer-director Nora Ephron tries to add some drama to the mix—there is a subplot, quickly dropped, involving the rise of McCarthyism, and Julia weeps in one scene for her failure to have children—but there is only so much that can be done when you are telling a true story about a woman who was innately good and mostly spared of tragedy in her life.

Amy Adams is a force of spirit in her own right as Julie Powell, and possibly has the slightly more developed and involving of the two storylines. Julie's rise to triumphs big and small and her renewed sense of purpose are warmly portrayed, as is her own respective marriage to Eric. Stuck in a rut that she hopes to get out of—she is unhappy in her career and longs to move from their quaint Queens apartment—Julie is determined to complete the task she has set before herself and is left most inspired by the words and seeming wisdom of Julia Child herself. For what it's worth, the sight of the recipes she makes throughout are definitely not for the hungry of stomach.

A handful of small, but key, supporting performances add flavor and personality to the leisurely proceedings. Linda Emond (2008's "Stop-Loss") is a charismatic partner-in-crime for Julia as friend and collaborator Simone 'Simca' Beck. Jane Lynch (2008's "Role Models") is a blowsy scene-stealer as Julia's younger but equally tall sister Dorothy. Mary Lynn Rajskub (2009's "Sunshine Cleaning") works wonders with her too-few scenes as Julie's brutally honest best friend Sarah. And Deborah Rush (2006's "Strangers with Candy") disappears into the mousy Avis De Voto, Julia's longtime pen pal. This latter subplot, with Avis and Julia meeting for the first time, doesn't really go anywhere of note and, despite Rush's nice work, could have easily been cut from the somewhat overlong finished product.

As "Julie & Julia" approaches its final act, one plot development is brought up and unnecessarily puts a wrinkle in things. When Julie receives a phone call from a magazine telling her that Julia Child, at the time in her early nineties, has heard of her blog and found it to be foolish and Julie to not be serious enough, Julie is crushed. Did her idol really say those hurtful things about her? The viewer patiently waits for this claim to be disputed, or for Julia's words to have been misconstrued by the press, but nothing more comes of it. That Julie and Julia never actually met or spoke prior to Child's death in 2004 is anticlimactic enough, but for Julia to be painted near the end as curmudgeonly by a third party serves no purpose other than to shine a sudden negative light upon this iconic figure. This dangling thread puts a damper on the otherwise gentle and heartwarming conclusion to both Julie's and Julia's tales. What it cannot do is lessen the sterling work of Meryl Streep and Amy Adams. They may not share any scenes together, but their collective work helps to make "Julie & Julia" sizzle even through its rougher patches.