What does it take for a chef, a restaurant, to earn that coveted “Michelin star?”

Attention to detail, fanatical care put into every stage of food preparation — from recipe experimentation to produce and meat selections —  insane hours, ridiculous stress and the patience of all involved to put up with this.

“42 Grams” follows a Chicago couple, from running an “underground” (illegal, off the books, unzoned, unlicensed, uninspected) restaurant out of their apartment, which they cheekily name Sous Rising,, to their opening a real restaurant and vigorously pursuing a Michelin restaurant guide star rating. Or two.

Jake Bickelhaupt and Alexa Walsh figure that since, as tradition (weighing someone just before and after death) and movies have taught us that the soul weighs 21 grams, they will call their intimate eatery “42 Grams.” They’re putting everything they’ve got, body and soul, into it.

Filmmaker Jack C. Newell only focuses on them, and we only hear about the life that’s passing all around them off camera. Three parents have died during their pursuit, a weeping Alexa says at one point. Jake is drinking too much. Their marriage is strained. There’s no time to start their own family.

Not when chef Jake, working class, largely self-taught and ego-centric (he knows all the words to the country music spoof, “You Never Even Called Me By My Name”), is furiously concocting ornate dishes, pureed baked banana topped with tamarind gelato, shaved hazel nuts and this and that, tiny salads you finish off with tweezers, itsby bitsy servings of duck surrounded exotic delights, caviar served inside hollowed quail eggs.

The food detail in Newell’s film is unsparing. Assorted assistants, “stages” (pronounced “stahje” in French, essentially unpaid interns) mostly, Jake and Alexa taste and re-taste versions of every absurdly labor-intensive dish.

Well-heeled customers, from the pretentious, adventure-seeking “foodies” who frequented their infrequent supper club evenings — a dozen seats in a tiny apartment right next to Jake preparing each meal, Alexa and a hired waitress serving them — to the patrons of 42 Grams, a failed fast food chicken joint underneath Chicago’s El they remake in their Sous Rising image (intimate, with the chef right in front of you) dine in wide-eyed, lip-smacking (and food “selfie” taking) delight at the taste sensations Jake serves up.

Both are quiet eating experiences, no music, with food and conversation all that’s there to cover up Jake’s short-tempered exasperation with his staff (sotto voce, maybe not sotto enough) in an open-plan kitchen.

Newell’s focus on the couple, their dreams, the prep and the food shows them leaving it all on the plate. This is taking everything they have to pull off, and Jake is hellbent on opening to a two star Michelin rating.

Jake is quick to point out what he regards as short-cuts, sell-outs, ennobling the pursuit of serving others great food while eschewing the “Food Network star” chefs who leave their restaurants in the care of others while they do TV, book tours and the like.

He never seems to consider that’s how Anthony Bordain developed a drug problem (and never became famous for his cooking) or Gordon Ramsay, Emeril and others were able to live life rather than letting the obsession eat every hour of their lives.

And Newell’s myopic focus on the couple leaves out the obvious — the business model. How much does it cost, per plate, to make a profit. Alexa glibly dismissing “commercial success” (i.e., rewards for your labors) just makes me that much more curious about prices, the evening meal turnover necessary for them to be able to afford to keep all this going.  (If you want to know what happened AFTER the credits, google Alexa Walsh.)

Thus “42 Grams” is eye-opening and engrossing, but no more so than your average episode of Ramsay’s old “Kitchen Nightmares” show. Less faked conflict, perhaps, but less revealing as well.

MPAA Rating: unrated, lots of profanity

Cast: Jake Bickelhaupt, Alexa Walsh

Credits:Written and directed by Jack C. Newell. A Gunpowder and Sky/Netflix release.

Running time: 1:22