Post vs. Post: The True Breakfast Rivalry That Inspired Netflix’s ‘Unfrosted’ Pop-Tarts Film

Jerry Seinfeld, famous for the NBC sitcom Seinfeld, has rarely pursued leading roles in live-action movies. He has preferred cameos (such as in 1996’s Eddie), animated features (like 2007’s Bee Movie), and documentaries (including 2002’s Comedian). This changes on May 3, when he stars in Unfrosted, a Netflix film he co-wrote and directed.

What drew Seinfeld out of his film hiatus? The fascinating backstory of Pop-Tarts, the iconic frosted pastry that debuted in 1964.

While Seinfeld may take creative liberties with how the breakfast pastry was invented, the real story is dramatic enough. It involves rival cereal giants, a rushed announcement, and a fierce competition to launch the first pre-toasted treat for American households.

A Delicious Dilemma

Postwar America presented a golden opportunity for the cereal industry. As more women joined the workforce and parents worked longer hours, traditional breakfasts became harder to prepare. Pouring cereal and milk into a bowl offered a quick and convenient solution.

By the 1960s, Kellogg’s dominated the cereal market as the industry giant. Known for Corn Flakes, Frosted Flakes, Corn Pops, Rice Krispies, and other popular cereals, the company controlled 44 percent of the market—more than its top competitors, Post and General Mills, combined. Both Kellogg’s and Post were headquartered in Battle Creek, Michigan, closely monitoring each other’s moves.

Post, known for products like Alpha-Bits, Grape-Nuts, and All-Bran, aimed to capture more breakfast moments with consumers. In 1963, executives thought they had a breakthrough by adapting a packaging technique pioneered by dog food expert Clarence Gaines, who had developed a way to keep wet pet food fresh in foil instead of cans.

Post, which had bought Gaines’s company, realized it was possible to create a shelf-stable, fruit-filled pastry that could be warmed and enjoyed. (For humans, of course.) The treat stayed slightly moist to prevent drying out, while bacteria and mold were kept in check. In the food industry, these were known as “intermediate moisture foods,” a category that later expanded to include granola bars, pie crusts, and military rations.

Post named the pastry Country Squares. Executives were so enthusiastic that they announced the product in 1963—long before it was ready for nationwide release. Instead, Country Squares were introduced to media and consumers in specific test markets like Seattle and Minneapolis, giving Post time to refine the product.

The company promoted them as “little tartlets” that came out “piping hot.” Flavors featured grape, strawberry, blueberry, and orange pineapple, each providing “a quarter of an adult’s daily requirement of six essential vitamins.”

In the fiercely competitive cereal market, revealing your plans was risky. When Kellogg’s chairman William LaMothe learned about Country Squares, he immediately tasked his team with developing a rival pastry and rushing it to market. This sparked a breakfast version of the space race, with both food giants striving to push the boundaries of what was thought possible.

A Story of Two Posts

While Kellogg’s excelled in cold cereals, they lacked the expertise to develop toasted and processed pastries. For assistance, they reached out to another Post: Bill Post, an Army Air Force veteran and seasoned food manufacturing expert who managed a facility for the Hekman Biscuit Company (later known as Keebler) in Grand Rapids, Michigan. (To avoid confusion, we’ll refer to the Post company as Post Cereal and Bill Post as Post.)

According to Post, he received a call and a visit from Kellogg’s executives who were eager to create a shelf-stable pastry but lacked the know-how. All they brought, Post remembered, was some dough and filling as a starting point.

“In 1964, I answered the phone, and Kellogg asked if they could visit to inspect some of our equipment,” Post told WWMT in 2021. “I agreed. They toured our plant … They mentioned wanting a toaster-friendly product but had no idea how to make it.”

Post began tackling the challenge of mass-producing the pastries. To create them, he needed two large sheets of dough encasing a layer of fruit filling. Producing these on a large scale required building a massive 60-ton pressing machine.

“There were so many doubters,” Post recalled. “Even some of my closest friends would say, ‘I’m not sure, Bill.’ They thought it wasn’t a great idea.”

Post also had to finalize a recipe. For several months, he brought samples home for his children to taste, gathering their thoughts on both flavor and texture. Eventually, Kellogg’s decided on four flavors: blueberry, strawberry, brown sugar cinnamon, and apple currant.

While Post Cereal delayed with Country Squares, Kellogg’s and Post worked swiftly on their version. They named it Fruit Scones, and within six months, it was ready for a test launch in Cleveland.

Tart Blanche

Kellogg’s still faced challenges. The initial Fruit Scones had rounded corners, but switching to square edges cut costs. Like Post Cereal, Kellogg’s initially aimed at busy adults, but testing revealed kids loved the toasted pastry while adults were less impressed. Marketing shifted focus, and Kellogg’s rebranded the product as Pop-Tarts, inspired by the 1960s pop art movement and the pastries’ ability to pop out of the toaster.

Kellogg’s launched Pop-Tarts nationwide in 1965, outpacing Post Cereal and leaving one Post Cereal employee to lament that Country Squares were essentially doomed. (Even a rebrand to Toast ‘Em Pop Ups didn’t help.) Kellogg’s increased production from 10,000 to 45,000 cases and still sold out, prompting the company to issue ads apologizing for low stock.

But Post wasn’t finished innovating. In 1967, he created a frosting for Pop-Tarts that stayed intact after toasting, using a cookie-icing machine. By 1968, Pop-Tarts featured sprinkles, and by 1974, they had their own mascot, Milton the Toaster. Breakfast pastries became a $45 million industry, with Kellogg’s dominating the market.

Post later worked as a consultant for Kellogg’s and occasionally spoke to journalists. After retiring, he often brought Pop-Tarts to share with his senior group. When he passed away in February 2024 at 96, he was hailed as a key figure behind the pastry’s creation. (While Post is widely recognized for developing Pop-Tarts, Kellogg’s acknowledges employee Joe “Doc” Thompson and their internal “kitchen crew” for its development, stating that Post “played a significant role in co-creating” it; Post himself credited many collaborators.)

Pop-Tarts have also found uses beyond breakfast. They’re included in military rations and have even been employed in humanitarian aid for war-torn regions. When Somali pirates hijacked the Maersk Alabama in 2009—a story depicted in the Oscar-nominated film Captain Phillips starring Tom Hanks—officials used chocolate Pop-Tarts as part of the negotiation.

Pop-Tarts have stood the test of time, though not without issues. In 1993, reports surfaced that leaving Pop-Tarts in the toaster too long could cause them to catch fire, likely due to overheated corn syrup.

The tale caught the attention of national humor columnist Dave Barry, who conducted his own tests after consulting fire officials in Dover, Ohio. They had recreated a Pop-Tart fire scenario to examine claims of a kitchen fire caused by the pastry. Both Barry and the Dover fire team reached the same verdict: Holding a Pop-Tart in a toaster for over five minutes could lead to disaster. If any real-life incident is likely to feature in Unfrosted, it’s probably a Pop-Tart catching fire.