Debra Messing expounds on the preciousness of life in a production that aspires to convey eloquent whimsy, but too often feels methodically sentimental.Repetition can make magic happen: repeat a word or a phrase enough times and it breathes new life, fresh meaning. Or repetition can strip language until all that’s left are empty rhythms and sounds. Words are funny like that.Noah Haidle’s “Birthday Candles,” which opened on Broadway Sunday night at the American Airlines Theater, tries to build poignancy and depth through moments that repeat like a record needle stuck in a groove. Instead, this Roundabout Theater Company production gets caught in a superficial cycle of wannabe profundities and emotional pantomimes.“I am a rebel against the universe. I will wage war with the everyday. I am going to surprise God!” So declares the precocious 17-year-old Ernestine (Debra Messing) as the show opens. It’s her birthday, and her mother (Susannah Flood) is making golden butter cake; it’s a tradition, one that Ernestine clings to for years, baking the same cake for herself over 90 birthdays, which we live through with her in the course of the 90-minute play.Messing, center, as the teenage Ernestine and Susannah Flood as her mother.Sara Krulwich/The New York TimesWith a fanciful offstage chime Ernestine instantly skips from one age to the next, though at an inconsistent clip — sometimes a year, sometimes a decade, but we’re always on her birthday, and she’s always baking her cake. (Messing beats the eggs, creams the butter and mixes the batter in real time, making this sugar-addicted critic wonder: Where are our slices?)As she bakes, the details of her life fill in around her: Family members and friends enter and exit, are born and die. With a chime her high school crush, Matt (John Earl Jelks), becomes her husband. Another and they have a teenage son, Billy (Christopher Livingston), and a daughter in college, Madeline (Flood, heartachingly tragic), and before Ernestine knows it Billy is ready to propose to his hopelessly neurotic girlfriend, Joan (a delightful Crystal Finn).All the while Ernestine’s lovesick friend Kenneth (Enrico Colantoni, adorable at any age) casually strolls in unannounced, carrying a torch for her for decades.With ordinary characters expounding on the preciousness of life, “Birthday Candles” aspires to convey eloquent whimsy — births, deaths, love, despair, whole constellations of human feelings and thoughts — but it’s Christine Jones’ wondrous set design that wordlessly manages the trick.A homey powder-blue kitchen is framed by three door-less thresholds on the left, right and center — each one representing passage into the house or the outside world, or a more metaphysical passage into the afterlife. Dwarfing the kitchen is a night sky messy with floating objects — keyboard, tricycle, dollhouse, umbrella, soccer ball, a teddy bear with his right arm extended, left paw positioned over his face as though in embarrassment or fear.It’s there that we neatly see how the personal can meet the universal. Down below, though, we are dutifully following an unrelenting parade of progeny embodied, “Lehman Trilogy”-style, by Flood, Finn, Jelks and Livingston. At some points it becomes a hassle to see the view from Ernestine’s family tree, given how quickly figures in her life disappear, and how children transform into grandchildren, then great-grandchildren.These shifts are tough work for the actors, who must often convey their characters’ varied ages in succinct lines: a lifetime in just a few minutes. Most of the cast, particularly Messing, who delivers an awkward caricature of a teen and then the exaggerated hand-wringing and dithering warble of an old woman, struggle in the sunrise and sunset years.Vivienne Benesch’s direction exaggerates the methodical sentimentality of Haidle’s script, allowing broad, clichéd gestures to do shorthand work. The teens, slouching from one end of the stage to the next, are unbearably self-righteous. (“You’re a shadow in a suit posing as a human, you should be ashamed of yourself,” sneer the teenage avatars of two generations, in one of the play’s funnier repetitions.) And the middle-aged adults wilt into the weary postures of seniors, with their sighs and ailments, right before our eyes.The shifts are tough work for the actors, who must often convey their aging characters in a few lines. Late in life, Messing’s Ernesteine is flanked by (from left) Flood, Enrico Colantoni, Christopher Livingston, Jelks and Crystal Finn.Sara Krulwich/The New York TimesAs Ernestine shuffles closer to a century of birthdays, the metamorphoses lean into emotional manipulation. We watch one character suddenly going slack, his face twisting and his hands stiffening in place, as if suffering a stroke. It’s unsettling, but for anyone who has seen family affected by illness, such transitions feel gauche; a quick change in posture and a handful of lines meant to represent the monumental losses we reckon with in, as Ernestine calls it, “the daily human errand.”“Birthday Candles” nearly suffocates in such grandiloquent pronouncements and existential metaphors. Ingredients for the birthday cake include not just the usual pantry staples but “stardust, the machinery of the cosmos” and “atoms left over from creation.” Characters recite lines from “King Lear” so as to share the mad monarch’s rantings about the nature of life and the passage of time.Even a poor goldfish, a nonunion actor in a round bowl on the kitchen table, works his tail off as a stand-in for what Kenneth calls “the divinity within yourself.”In some ways this reach for the cosmic comes with the territory. In surreal plays like his 2016 “Smokefall,” Haidle aspires to mix multigenerational family drama and poetic musings. And he acknowledges that this work, his Broadway debut, is inspired by Thornton Wilder’s “The Long Christmas Dinner,” which, like his classic “Our Town,” employs chronological jumps as a means of considering love, life and death in the stories of everyday people.At its most strained, “Birthday Candles” feels like an imitation of a superior work. The time-hopping conceit doesn’t allow us to get a real sense of the world beyond Ernestine’s kitchen. That said, there were plenty of empathetic sniffles and sighs in the audience during the performance. The most moving moments to me were those quiet exchanges that functioned as silhouettes for unspoken griefs. After one devastating loss, Ernestine and Matt bake a cake together in a weighty silence; after a few seconds he walks away, head hanging like a half-mast flag on a windless day.Ernestine’s story predictably finishes by circling back to the beginning — cake, stardust and atoms. Allow me to end with my own dose of carefully administered déjà vu: repetition can make magic happen. But real magic comes from the forward-march of a life whose everyday rhythms may repeat, sure, but still leave room for accident and chance — the most sensational improvisation.Birthday CandlesThrough May 29 at American Airlines Theater, Manhattan; roundabouttheatre.org; Running time: 1 hour 30 minutes. 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