The breezily entertaining first half hour of “Sitting in Bars With Cake” gives little indication that the Prime Video film will become a half-the-Kleenex-box tribute to enduring, unshakeable friendship. Those first minutes play as a high-concept romantic comedy in which a new-to-Los Angeles young woman (Yara Shahidi, ABC’s “Grown-ish”), at the urging of her lifelong best friend and roommate (Odessa A’zion, last year’s “Hellraiser” reboot), bakes cakes to take to clubs to attract men.

Bette Midler’s presence in this film about two childhood friends should have tipped us off. But Midler’s performance as Benita, head of the entertainment agency that employs Jane (Shahidi) and Corinne (A’zion), is so uncharacteristically low-key you almost miss the parallels of this film to “Beaches,” the 1988 five-alarm tearjerker where Midler plays an over-the-top showbiz pal to the quieter Barbara Hershey. Here, Benita is demanding and dismissive, but never outlandishly so, given her powerful position.

Midler’s performance matches the understated authenticity that runs through “Sitting in Bars With Cake” and eases its transition from gals-on-the-town romp to illness-centered drama. Director Trish Sie and screenwriter Audrey Shulman, who based her script partly on her life and 2015 cookbook, merge two often creatively dicey forms — romantic comedy and weeper — into a cohesive, affecting film. This is especially surprising given Sie’s biggest previous credit was 2017’s underwhelming “Pitch Perfect 3.”

This film’s most authentic element is Shahidi and A’zion’s chemistry, which helps us believe the buttoned-up Jane and free-wheeling Corinne would do anything for each other. Such a solid friendship makes everything a little less scary, whether it is moving from Arizona to L.A. or confronting Corinne’s eventual cancer diagnosis.

The pals don’t finish each other’s sentences but rather punctuate those sentences with quips. The rhythms of their interactions — gentle teasing that always comes from a foundation of support, subtle questioning when the other friend does something not in her self-interest — bespeak thousands of interactions that came before. Their bond has flourished, in part, because they complement each other.

简,在该机构工作的邮件收发室而以ring for law school to please her successful lawyer parents, is too shy to approach the guy she likes at work, or any guy for that matter. She blows off steam by making inventive cakes, including one whose last-minute addition of crumbled cocoa cereal is this film’s equivalent of the chips on the omelet in “The Bear.”

Corinne, Benita’s assistant and an aspiring agent, recognizes baking cakes as a low-risk dating calling card for her more introverted friend after a cake Jane baked for a party at a nightclub is a big hit with strangers.

Jane, in turn, provides order for Corinne. But they are not “Odd Couple” stereotypes. Corinne is not sloppy, and pays her rent on time, even if it is at 11:59 p.m. on the first of the month (a perfect character-encapsulating detail).

“Sitting in Bars With Cakes” captures that special time in one’s 20s when stamina, optimism and a first infusion of disposable income make going out to bars seem like a mandate. And the various bars and nightclubs the friends visit appear to be real, lively places rather than blue-lighted facsimiles created on soundstages. The only obviously unrealistic aspect of the film’s premise is that people downing booze all night would want cake. But “Sitting in Bars With Tacos” would lack the visual payoff of this film’s many shots of perfectly rounded and decorated cakes.

Neither Corinne nor the film, thankfully, lose their irreverent spirit after Corinne’s diagnosis. Ron Livingston (“Office Space,” “Sex and the City”) and Martha Kelly (“Euphoria”) lend worry and warmth to their roles as her parents, with the former providing comic relief as a compulsive Mr. Fix-it who copes by planning projects around the apartment.

The time spent establishing Jane’s and Corinne’s bond pays off by always keeping their scenes on the heartfelt side of maudlin. But at two hours, the film still feels long, with too much attention focused on a romantic storyline with Jane and a colleague that goes nowhere. We would have rather spent more time with Jane and Corinne, the relationship that really counts.

Carla Meyer is a freelance writer.