Directing a feature for the first time, the sitcom legend also stars in the Netflix movie as a cereal company executive involved in the race to create a toaster pastry.

If you appreciated Barbie’s eye-popping zaniness but its virtuous speechifying set your teeth on edge, have I got a sugary treat for you. And by “sugary,” I mean empty calories, not saccharine sentimentality. Gleefully silly — this is, after all, the directing debut of TV’s master of the domain of nothing — Unfrosted takes the origin-story template, wrings it dry of emotion, mixes basic facts with goofy fiction and serves up a bit of toasted history about the search for a “fruit-filled pastry dingus,” the 20th century creation we now know as the Pop-Tart.

For buffs of any age, Unfrosted abounds in affectionate and jokey movie and TV references. And there are endless nods to ’60s pop culture totems (in the opening minutes alone, Woody Woodpecker, the Slinky and G.I. Joe make fleeting appearances), but whether anyone born after 1963, the year the movie takes place, will get most of them is another question. It should be noted, too, that Seinfeld’s recent stances on divisive political issues will make it difficult for even some longtime fans to wholeheartedly embrace him anymore. But for those willing to put aside reality for 90 minutes, as Unfrosted does with gusto, the Netflix movie whips up a frothy sendup of storytelling tropes and clichés.

A couple of dumpster-diving kids (Eleanor Sweeney and Bailey Sheetz, both aces) have clued in exec Bob to Post’s advances on that front. In an evil-looking edifice across the street, the turbaned and ruthless Marjorie Post (Amy Schumer) and her relentlessly abused right-hand man (Max Greenfield) are ready to launch their new product, though whether they’ll call it Dextrose Dillies or Fresh Flatties has yet to be decided. Upping its game, Kellogg’s holds a press conference, straight out of The Right Stuff, to introduce its team of “taste pilots,” a mix of historical and invented figures played by James Marsden, Jack McBrayer, Thomas Lennon, Bobby Moynihan and Adrian Martinez, with a cameo by the Univac computer.

Bob and his boss, the affably gruff and gruffly affable Edsel Kellogg III (a pitch-perfect Jim Gaffigan), are not only feeling the toaster-pastry existential pressure, but are also dealing with labor unrest among disgruntled cereal mascots. Leading the push is a Shakespearean actor slumming it as Tony the Tiger (Hugh Grant, lending a Brit slant and delicious intensity to the real-life Thurl Ravenscroft), while Snap, Crackle and Pop (Kyle Mooney, Mikey Day and Drew Tarver) are convinced they’re being held back from realizing their career potential.

At the helm of a cast filled with virtuosos of comic timing, Seinfeld draws performances that are, for the most part, understated, effectively heightening the ridiculousness of the setup by playing it straight. The cavalcade of cameos climaxes with a supremely apt and satisfying surprise, and along the way there are meetings with JFK (Bill Burr), Khruschev (Dean Norris) and the boss of Big Sugar (Felix Solis). The milk syndicate is headed by the incongruously named Harry Friendly (Peter Dinklage), while Bob’s neighborhood milkman (Christian Slater) has an especially menacing smile. Lest you forget that breakfast is serious business, a quintet of cereal manufacturers meet in the thick of night, à la The Godfather’s Five Families.

Not all the bits land, though, and the story hits a momentum lag midway through. But at its strongest, the movie delivers spot-on spoofs of shopworn narrative devices — the chalkboard brainstorming scene, for one.

Best of all, there’s not a drop of corporate mythologizing in the mishmash of factoid and fantasy. Seinfeld’s love of packaged breakfast foods might color this movie’s world, but far from an ode to product integrity posing as thoughtful and irreverent, Unfrosted tosses off Pop-Tart putdowns as fast as you can toast ’em. Nothing is sacred here. I could have lived without the Gus Grissom jokes, but it’s refreshing to see the perpetually valorized Walter Cronkite (Kyle Dunnigan) as something of a pathetic buffoon.

The closest the movie gets to unadulterated sweetness is in its framing device involving an adorable runaway boy (Isaac Bae). Here too, though, Seinfeld wisely withholds the sugar frosting, even if Kellogg’s eventually decided otherwise.