Surprising secrets of the perfect sandwich, from a cookbook author and social media star

Owen Han knows a few things about sandwiches.

The Los Angeles-based TikTok creator, dubbed the "Sandwich King," has amassed millions of followers and is the author of a new cookbook titled "Stacked: The Art of the Perfect Sandwich." 

Speaking to Fox News Digital on Zoom from his hotel room in New York City, Han divulged some of the secrets behind his wildly successful TikTok account and offered a few tantalizing tips on how to make the best sandwiches. 

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Han did not seek out a career in sandwich-making, he said. 

"It kind of happened by chance," he said. "I've always loved sandwiches."

Sandwiches, he said, are his "ultimate comfort food."

After prodding and encouragement from his roommate, Han said he began posting sandwich content on TikTok. He quickly found success. 

The first meal he filmed was the creation of a "chicken bacon avocado sandwich," something he did not intend to make. It happened to be based on the ingredients he had on hand.

"It was my first video to break a million views," he said. "And so I guess it really resonated with people." 

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Having tasted viral success, Han decided to try again with another video – this time, with a steak sandwich. 

That video "completely took off," he said, receiving over 10 million views. 

"People were calling me the ‘sandwich guy,’ right off the bat," Han said.

Eventually, there were calls for Han to write a cookbook of his sandwiches, something he said was not what he envisioned back when he first posted his chicken bacon avocado sandwich on TikTok. 

"Stacked" contains sandwich recipes for every occasion and every skill level, he said, from absolute beginners to seasoned pros in the kitchen. 

There's also a section of dessert sandwiches, which he said "gave him a sweet tooth."

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Despite being known on TikTok as the "Sandwich King," one thing Han said he is not is a "sandwich purist." 

His definition of a "sandwich" is "very loose," he told Fox News Digital. 

"If the ingredients are stackable and in between a carb source – so that includes cookies, tortillas, wraps, bread, of course – and can be eaten with your hands and sometimes a fork and knife – then, in my literal book, it's a sandwich," he said.

That includes hot dogs and burritos, as well as tacos and bao.

"I'll definitely get a few comments here and there [from people who say], 'That's not a sandwich,'" he said. 

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"For me, the most important [ingredient] has to be the bread," Han said, adding that he goes to "multiple bakeries" to get the perfect loaf for the sandwich he is creating. 

"For me, bread can absolutely make or break the sandwich," he said. "It's the foundational key ingredient." 

Switching out the bread type, Han said, can serve to "elevate your sandwich game."

"The way in which you assemble [the sandwich] is pretty important," Han said. "There's a whole section in the book" about the topic, he added. 

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Being mindful of the order of ingredients "gives the sandwich structural integrity," he said. 

"You don't want ingredients falling out of the sandwich when you go in to eat it." 

When crafting a sandwich, Han said, avoid putting wet ingredients on the bread so that the sandwich doesn't become soggy or "overly wet." 

"No one really wants that, unless you're doing a French dip or something," he said. 

Han, who is of Chinese and Italian ancestry, likes to mix things up when it comes to sandwich traditions, he said.

"I like to put my own twist on [sandwiches]," he said. "So, in my cookbook, I have a ‘Not-So-Classic Cheesesteak’ where I draw inspiration from my heritage." 

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For his cheesesteak, Han uses "Chinese-inspired Beijing beef for the meat," then tops the sandwich with mozzarella cheese and Italian pickled peppers.

In his Korean Reuben sandwich, Han subs kimchi for the traditional sauerkraut. 

The flavor combination of a traditional Reuben with kimchi "works so well," he said.