They’ve been making a hot breakfast possible for anyone who owns a toaster for over five decades, but even if you’ve munched through box after box of Frosted Strawberry and Brown Sugar Cinnamon, you may not know all of the sweet inside scoop on Pop-Tarts.

1. A Competitor’s Business Blunder Made Them Possible.

Kellogg’s Pop-Tarts are breakfast icons, but the company’s cereal rival Post actually had the idea to make a toaster pastry first. In early 1963, Post announced a line of shelf-stable pastries called Country Squares diners could heat up in their toasters. The idea was promising, but Post had made a critical error in its announcement: Country Squares were months away from being ready to go to market. Rather than springing the new breakfast treats on an unsuspecting Kellogg’s, Post gave the competition a chance to develop an answer to Country Squares. Kellogg’s began scrambling to make a pastry it could rush onto store shelves.

2. Kellogg’s Brought in an Expert to Perfect the Product.





If Kellogg’s was going to beat its rival to the breakfast-pastry punch, it would need to round up some baking help. Naturally, the company turned to Keebler. In September 1963, Bill Post, the manager of Keebler’s Grand Rapids, Mich. Plant, started working on what would become Pop-Tarts. Post, the son of Dutch immigrants, had been working at Keebler since his 16th birthday. If anyone had the baking know-how to quickly create a toastable treat, Post was the man.

3. Bill Post’s kids played a key role in the taste testing.





Before Pop-Tarts were Pop-Tarts, they were just product samples that Post would bring to his kids. As he recounted to Northern Express in 2003, Post first realized these particular pastries might take off when he shared them at home: “I used to bring a lot of samples home, and they‘d turn up their noses at some of them. But they‘d say, ‘Bring those fruit scones home.‘ That‘s what we called them at first, fruit scones. ‘Bring some of those home, will you, Dad?‘”

4. Cleveland Got the First Taste of Pop-Tarts.





After Post’s children helped convince him that Pop-Tarts were ready for store shelves, Kellogg’s tested the pastries in the Cleveland market in late 1963. They were an instant hit, and four flavors of Pop-Tarts – strawberry, blueberry, brown sugar cinnamon, and apple-currant – rolled out nationally in 1964. As Post remembered in 2003, the success of the Cleveland test convinced Kellogg’s to boost the first national production shipments from 10,000 cases to 45,000 cases of pastries. The entire run sold out anyway.

5. They Come in Pairs for a Reason





In her book Better Than Homemade: Amazing Foods that Changed the Way We Eat, Carolyn Wyman solves a Pop-Tart mystery. If the serving size for Pop-Tarts is just one pastry, why do they always come packaged in pairs? Bill Post revealed that the decision had more to do with economics than portion control. The machines needed to wrap Pop-Tarts in foil weren’t cheap, and when the pastries were still unproven commodities, Kellogg’s didn’t want to make any unnecessary investments. By doubling down on how many tarts went into each packet, the company could cut its machinery budget in half. By the time Pop-Tarts were a hit, consumers were used to the double packages.

6. The Original Pop-Tarts Were Subtly Different from Today’s Tarts.





Fans of modern frosted Pop-Tarts might mistake those first batches from 1964 with any of the legions of knockoffs that have sprung up in the intervening decades. The original Pop-Tarts had rounded corners instead of the square ones we’re now used to, were marked with a long diagonal score to facilitate splitting, and didn’t feature frosting. The scoring eventually fell by the wayside because it made it more difficult to see the fruit filling in each half of the Pop-Tart.

7. The Holes Are an Important Design Feature.





An Ad Week story from June revealed the way in which those “docker holes” are a crucial part of every Pop-Tart’s makeup. Without the holes, steam would collect in the pastry as it toasted, resulting in a soggy Pop-Tart.

8. Kellogg’s Brass Was Skeptical of Frosted Pop-Tarts.





After Bill Post’s triumphant national introduction of Pop-Tarts in 1964, he elevated the treats into the breakfast staple we know and love with the addition of frosting in 1967. The first prototype frosted versions were the result of sending regular Pop-Tarts through a machine used to ice cookies. When Post’s boss was concerned that frosting wouldn’t be able to withstand a toaster’s heat without melting, Post walked into a meeting carrying a toaster to demonstrate the durability of the sugary stuff. Kellogg’s execs gave him the go-ahead to start frosting the entire Pop-Tart line just minutes after the meeting ended.

9. Unfrosted Pop-Tarts Pack More Calories Than Frosted Ones.





Princeton sophomore Spencer Gaffney kicked off years of confusion and curiosity with a 2009 blog post in which he unearthed a strange fact: Frosted strawberry Pop-Tarts contained 200 calories each, while the unfrosted versions were a stouter 210 calories a pop. How could skipping the sugary frosting result in a more calorically dense breakfast treat? Earlier this summer, Quartz finally solved this enduring riddle. The crust on unfrosted Pop-Tarts is just a little bit thicker than it is on their frosted brethren, which results in a net gain of calories if you grab the seemingly healthier option.

10. They Can Generate Terrifying Flames.

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Since at least the early 1990s, Pop-Tarts have been blamed for causing numerous house fires following toaster mishaps. The Philadelphia Inquirer reported in 2001 that the pastries had been implicated in at least 17 fires and explained that the heat of a toaster could ignite the corn syrup in the filling, which would then cause the crust to burst into flames. This finding jibes with a playful 1994 “study” in which pastries that weren’t ejected from a toaster shot 20-inch flames. While these fires are uncommon, they demonstrate why Kellogg’s clearly warns consumers not to leave an unattended tart in the toaster.

11. You Can Buy or Make Fancy Fresh Baked Versions Now.





It feels like there is at least one small company out there making an artisanal version of any snack you can think of, and Pop-Tarts are no exception. Since 2012, Brooklyn-based Megpies has been making gourmet versions of the venerable toaster treats for discerning eaters. The company offers handmade takes on familiar flavors like strawberry, blueberry, and cinnamon brown sugar alongside newer combos like salted caramel apple. You can order them online here, or if you’re feeling industrious, you can grab a recipe and try making your own.