I was told there would be cake.

Or rather, I imagined the cake, thinking I’d find something delectable about “Dirty John,” Bravo’s eight-episode limited series based on the gripping true-crime podcast and narrative series by Los Angeles Times reporter Christopher Goffard. In addition to drawing on Goffard’s riveting reporting — about Debra Newell, a wealthy Orange County businesswoman who fell for a charming and dangerous grifter named John Meehan — the drama stars Connie Britton, the patron saint of one-hour dramas.

Alas, “Dirty John,” created by former “Desperate Housewives” writer-producer Alexandra Cunningham, leaves a lot to be desired, judging by the three episodes made available for this review. The show officially premieres Nov. 25, but Bravo has already made the first episode available on its website in an apparent attempt to capi­tal­ize on the excitement around the series.

Britton (of “Nashville” and “Friday Night Lights” fame) was an obvious choice to play Debra, described in the podcast as beautiful and put together, with layers of “cornsilk-blond” hair. When she meets John, she’s a divorcée, four times over, with four grown children and a thriving interior design business. She continues to believe in love and endures a sequence of bad dates in an effort to find it. Things feel different when she meets John, a handsome if somewhat scruffy anesthesiologist, who dotes on her. After a whirlwind few weeks of dating, well, you can probably guess what happens next.

Eric Bana plays Meehan with effective but rudimentary creepiness, and the show requisitely introduces us to the podcast’s major players, some of whom get name changes. By the end of the second episode, we’ve met Debra’s daughters, Veronica and Terra (Juno Temple and Julia Garner, respectively), her mother, Arlane (Jean Smart) and her nephew, Toby (Kevin Zegers).

The people and places — from the penthouse apartment Debra initially shares with Veronica to the beachside house she impulsively rents to hole up with her new beau — are all there, but the show doesn’t dig any deeper.

Bana’s sinister turn as John, whose self-described biography begins to crumble shortly after he woos Debra, doesn’t include any charm, which puts the show in shaky territory from the very beginning. We need to be able to imagine Debra falling in love with him, even if we can see the red flags, which are aplenty.

Debra’s daughters were integral to Goffard’s reporting in ways I won’t divulge here. But on-screen, they are reduced to paper dolls, acting (or, in many cases, overacting) out their podcast personas. It’s a real shame, because the Newell daughters — shy, sweet Terra and feisty Jacquelyn, the clear inspiration for Veronica — present an opportunity for the show to redeem itself with just the right amount of camp. “Dirty John” so thoroughly strikes out in this regard it’s hard to tell if the show even attempts it.

Veronica is immediately suspicious of John, who, she tells her mother, looks homeless and seems to be a little too interested in the expensive furnishings in their apartment. Temple so dutifully zeros in on Veronica’s edge that the character comes off as more bratty than anything else. Like Jacquelyn, Veronica has a love for designer handbags. That could be fun! Except it isn’t.

Garner, meanwhile overexaggerates the vocal fry of Debra’s zombie-obsessed daughter, Terra, but isn’t given much else to work with. (Where have you seen Garner before? “The Americans” and “Ozark,” but she’s rendered almost unrecognizable here by straight hair).

In other missed opportunities, family tension comes to a head in a Thanksgiving scene that is over far too quickly — so quickly, in fact, that I thought I must have missed something.

“Dirty John” gets moderately interesting in the third episode, which begins to delve into John’s past and previous marriage just as Debra is beginning to see his controlling and secretive demeanor. But it’s far too little, too late.

Part of my disappointment undoubtedly stems from having seen Ryan Murphy’s “People v. O.J. Simpson,” a drama that took a news event (albeit one that received much more coverage than John Meehan’s dirty deeds) and spun it into thoughtful and somehow timely commentary that was entertaining to boot. Murphy is a very specific type of storyteller, so it’s admittedly somewhat of an unfair comparison.

But so far, there’s little commentary to be found in “Dirty John,” which seems unforgivable in a year punctuated by widespread condemnation of toxic men.

I expected so much more. In the end, “Dirty John” only managed to spin a new con — promising dessert and delivering a plate of lukewarm leftovers.

Dirty John (1 hour) officially premieres Nov. 25 at 10 p.m. on Bravo. The first episode is available to watch now on Bravo’s website.