William "Bill" Post, who is credited as the inventor of Pop-Tarts, passed away last weekend on Feb. 10 in Grand Rapids, Michigan. He was 96.

Post, who was the son of Dutch immigrants as per his obituary, was serving as the plant manager of Keebler Company in the early 1960s, when he welcomed some executives from Kellogg’s who discussed the idea of a new product — a shelf-stable toaster pastry — they had in mind.

"It is at this juncture that Bill is often credited for having 'invented' the Pop Tart," Post's obituary reads.

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Kellanova, Pop-Tarts parent company, said that they were "deeply saddened" to hear about Post's death.

"He played an important role in co-creating the iconic Pop-Tarts brand and we are grateful to Bill for his legacy and lasting contributions to our company," Kellanova said in a statement to USA TODAY over email.

When were Pop-Tarts invented?

Pop-Tarts were first invented in 1963 after Kellogg chairman William E. LaMothe had the idea of "transforming a delicious breakfast into a toaster-ready rectangle that could go anywhere," according to Pop-Tarts. LaMothe pitched the idea to his kitchen crew, who initially developed it as a toast and jam pastry called “Fruit Scone.”

The name wasn't very appealing so the company "inspiration from the Pop Culture movement of the day and renamed it 'Pop-Tarts',” says Pop-Tarts on their website.

How did William 'Bill' Post contribute to creating Pop-Tarts?

In 1964, when Post was a plant manager at Hekman Biscuit Company, a regional baker that was part of the company that would later become Keebler, he was approached by Kellogg's who floated the idea.

In a video produced by Kellanova, in which Post visits the Kellanova plant in Grand Rapids, Post says that four vice presidents of the company came with "two pieces of dough with some filling in it".

"We have this idea. We'd like to put that in a toaster," they said to him.

Post said that his boss scoffed at the idea, but he liked it and decided to work on it.

“To get that done, I had to break every rule in the book,” said Post. He proceeded to make almost 10,000 samples by hand in the laboratory.

In a 2022 interview with Fox 17, Post said that the handmade samples were ready within four weeks.

“Within four months, we had a product that went to test market," Post says in the interview. "They found out that kids really liked them.”

'They just blew off the shelves'

The new creations were tested in different markets. Four original flavors - Strawberry, Blueberry, Brown Sugar and Apple-Current - were released in Cleveland, Ohio, in 1964, according to Pop-Tarts.

"Those just blew off the shelves," Post told Fox 17. "Kellogg's ran a big page ad that (basically) said, 'Oops! Sorry! We ran on a Pop-Tarts.' From then on, we've been running ever since."

As for his favorite flavor, Post told Fox 17 that his favorite was Strawberry.

Post did not stop there. He decided that the Pop-Tarts needed icing as well. And in 1967, Pop-Tarts got frosted.

"The decision to make all four flavors iced took one day," says Post in his video with Kellanova.

However, being the person that he was, Post did not take full credit for inventing the sweet snack.

"Bill would say, 'I assembled an amazing team that developed Kellogg's concept of a shelf-stable toaster pastry into a fine product that we could bring to market in the span of just four months'," reads his obituary.

Following Kellogg's split last fall into two independent, publicly traded companies, Pop-Tarts are now under the direction of Kellanova, with more than 20 flavors available. Almost 3 billion Pop-Tarts were sold in 2022, Kellanova told USA TODAY Wednesday.

A film about the invention of the popular breakfast pastry titled "Unfrosted: The Pop-Tart Story," directed by and starring comedian Jerry Seinfeld, is set to premiere May 3 on Netflix.

Post is survived by 2 children, as per his obituary and many grandchildren and great-grandchildren. His best friend and wife Florence passed away in 2020.

Saman Shafiq is a trending news reporter for USA TODAY. Reach her at [email protected] and follow her on X, the platform formerly known as Twitter @saman_shafiq7.

Contact reporter Greyson Steele at [email protected].