The title of Nora Ephron’s Julie and Julia equalizes its two plots: there is one about how Julia Child came to publish Mastering the Art of French Cooking and thereby alter the American palate, and there is one about Julie Powell’s efforts four decades later to cook her way through Child’s cookbook. But in truth these stories aren’t remotely on the same footing.

Child’s story begins after World War II, when Julia (Meryl Streep), a Pasadena debutante blessed with curiosity, verve and tireless optimism, accompanies her diplomat husband, Paul (Stanley Tucci), to Paris, where he’s obtained a job in the U.S. embassy. Casting around for somewhere to place her energies and enamored of French food, she enrolls in an advanced class at the Cordon Bleu cooking school. The institution’s finicky director (Joan Juliet Buck), a Parisian snob of the first order, tells her she has no talent for cuisine. But Julia befriends Simone Beck (Linda Emond) and her collaborator Louisette Bertholle (Helen Carey), who are preparing a French cookbook for Americans, and at their insistence Julia signs onto the enterprise.

Powell’s story begins with Julie (Amy Adams) depressed by her job of dealing with the survivors of 9/11 and exasperated that she hasn’t developed into the writer she planned to become. She gets the idea of matching her culinary skills against Child’s and recording her progress on a blog.

Whether creating scripts for other directors (Heartburn, When Harry Met Sally) or directing her own films (Sleepless in Seattle), Ephron has shown herself to be a comic screenwriter with a smug sensibility. Julie and Julia has some charm. Ephron works well with the actors and the movie looks lovely, especially in the Paris scenes, in which Stephen Gold blatt’s cinematography evokes the feeling of the city in the wake of the war and Ann Roth’s costumes flatter Streep while providing subtle notes on her character.

Streep’s performance redeems her shockingly cartoonish work last year in Mamma Mia! and Doubt. She catches you off guard with some of the warmest and most human acting she’s ever done. Her scenes with Tucci are robust and romantic.

Tucci squires her so generously that his own first-rate work is in danger of being underappreciated. It’s a pity that the plot that swirls around Paul—his liberal politics get him in trouble during the McCarthy era, and he is taken away from his Paris posting—is so poorly sketched. The further the Child narrative wanders from Paris, the weaker the screenwriting.

Luckily, Streep and Tucci are so marvelous together that it’s easy to overlook the holes in the screenplay. And when Jane Lynch shows up as Julia’s sister Dorothy, the two long-legged, goosey ladies are a deliriously perfect match.

Whenever the film swings from Julia’s story to Julie’s, however, we wonder why we should care about a woman whose only achievement is cooking her way through a famous French cookbook. Adams has great actor’s resources, but there’s no way to dramatize Julie’s story without making her look unpleasantly self-involved and her efforts trivial. The Julie plot contains no real conflict, and Ephron’s effort to invent one—an argument between Julie and her husband, Eric (Chris Messina, very likable in the role), that prompts him to move out of their Queens apartment for a couple of days—is unconvincing.

When focused on Julie, the movie seems to bide its time until it can get back to Julia and Paul. That makes the decision to end the movie with Julie’s visit to Julia’s kitchen, reconstructed at the Smithsonian, ill advised—as if Julie Powell is the true protagonist, or as if the heart of the movie is Julie’s bond with Julia and not Julia Child herself.