The first words of this food-fixated musical are ‘Sugar, butter, flour’, and though some of its ingredients are fluffy or icky it eventually whisks up a satisfying mixture of whimsy, warmth and sadness.

Based on a quirky 2007 film written and directed by Adrienne Shelly (who was randomly murdered three months before its release), it’s an admittedly lightweight story of a woman trapped by her circumstances, with a side order of occasionally eyebrow-raising sex comedy. But the ratio of sweet flavours to tart ones is well-judged.

Sara Bareilles has crafted a propulsive score and lyrics packed with poppy nostalgia. The best of them are soaringly delivered by Katharine McPhee, who’s engaging as the perpetually disappointed Jenna, a waitress in a diner who returns home each night to Earl, a dead-beat husband who is the definition of neediness.

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Jenna has a talent for creating elaborate pies, and her dreams of freedom focus on the $20,000 prize that’s improbably up for grabs at a local baking contest. But when she gets pregnant she finds herself in the office of David Hunter’s Dr Pomatter, a married gynaecologist whose sympathetic manner and rather clumsy brand of charm seem to promise a very different escape route.

Although Jenna can appear lost in fantasy, she’s a steady hand compared to the oddballs all around her. Her co-workers include Civil War obsessive Dawn, who’s given an amusing nerdishness by Laura Baldwin, and Marisha Wallace’s no-holds-barred Becky, while Jack McBrayer injects some outrageous slapstick as Dawn’s dorkish admirer Ogie.

Diane Paulus’s production is fluent without being unpalatably slick — there’s a discreet onstage band and artfully restrained choreography from Lorin Latarro. The show has cartoonish elements, but mostly subverts its moments of sentimentality and silliness, and there’s a whole lot of humour baked into it.

Until Oct 19