Can the "The Nanny Diaries'" writer-directors be put in timeout?

Ever made a cake, assembled from a delicious-sounding recipe and an array of fresh and delightful ingredients, only to find that it was a flat, unappetizing failure? (Not that I've ever, um, actually done this; it's just a for-instance.) Such is the case with "The Nanny Diaries," a movie made from a wickedly funny book, adapted and directed by a talented pair of filmmakers, and cast with a troupe of A-list stars. Maybe they forgot the baking powder — or, more likely, the wit got left out somewhere along the way.

The 2002 novel "The Nanny Diaries," written by ex-nannies Emma McLaughlin and Nicola Kraus, is one of the better books of its boss-from-hell type; its young heroine watches wide-eyed as her ultrarich employers simultaneously pamper and ignore their 4-year-old son in the name of Upper East Side parenting. But the movie, written and directed by Shari Springer Berman and Robert Pulcini (who made the wonderful "American Splendor"), takes some wrong steps from the start. Its satire is heavy-handed; its pace sluggish; its feel-good ending (not from the book) utterly misguided.

Annie (Scarlett Johansson), a recent college grad so clueless she wears anklets with a suit, accidentally falls into nannyhood while pausing in Central Park. Rescuing a kid (Nicholas Reese Art) from a near-collision, she meets his brittle, elegant mother, known only as Mrs. X (an impeccably controlled Laura Linney). A job is offered, and quickly accepted — better, Annie thinks, than the dull jobs in finance her mother (Donna Murphy) is encouraging.

But soon, the reality of the job sets in: She's underpaid, overworked, and expected to be both mother and father to little Grayer, all the while teaching him French and cooking him gourmet meals. The point — that parents should love their children, and that money can't buy happiness — isn't enough to sustain even a fraction of the movie's running time. Where the book filled in with humor, the movie just fills in.

Some of the book's funnier details do make it to the screen: the names of the Upper East Side kids (my favorite: Darwin); the poshness of the Parenting Center, where a group of expensively coiffed ladies earnestly discuss parenting while nannies take care of the children. And Springer and Berman add a sprinkling of charm by channeling that greatest of all nanny movies, "Mary Poppins": Annie's cellphone plays "Chim Chim Cheree," and she fantasizes herself floating, umbrella-borne, over Central Park.

But despite these efforts, there's just no movie here, and "The Nanny Diaries" plods along pointlessly to its flat conclusion. One unexpectedly funny detail does register: In a late scene, Grayer's scary grandmother sits in a beach chair engrossed in a book, ignoring her grandson. And what might she be reading? It's "The Devil Wears Prada," a "Nanny Diaries" tell-all cousin, and it reminds us, briefly, of a much better movie. Miranda Priestly, where are you? "The Nanny Diaries" needs you, and fast.

Moira Macdonald: 206-464-2725 or mmacdonald@seattletimes.com