Blaze Pizza is already the fastest-growing restaurant chain in America. Now, it's setting its sights on the rest of the world.

Blaze Pizza opened 68 new restaurants in the last year, reaching 173 locations across the US. The fast-casual pizza chain grew sales 84% in 2016, to $186 million from $101 million in 2015.

And while experts warn that the restaurant industry is overstuffed with options, co-founders Elise and Rick Wetzel believe there's plenty of room for growth.

The Wetzels founded Blaze Pizza in 2012. The chain prepares and bakes personal pizzas fresh to order on a Chipotle-like assembly line where customers can pick toppings from a selection in front of them.

The Wetzels think fast-casual chains like Blaze can beat out fast-food chains and eventually replace fast food altogether.

"There are too many fast-food restaurants," Elise told Business Insider. "People are not going to be satisfied with that. They want convenience, and health, and taste."

According to Rick, every new fast-casual restaurant that opens can serve as a replacement for a fast-food restaurant that shuts down. Blaze Pizza wants to be that replacement.

"With the McDonald's, and the Taco Bells – it feels like very over-engineered food," Rick said. "It feels unhealthy, whether that's true or not. It feels very old-school."

Blaze Pizza cooks its pies in a stone hearth oven for 3 minutes. Blaze Pizza

According to Rick Wetzel, the company's next big target is hitting $1 billion in sales, which would make Blaze Pizza the fifth-largest pizza chain in the US. As the chain expands, the co-founders want Blaze to compete head-to-head with delivery-centric, fast-food-style competitors like Domino's and Pizza Hut.

"Make no bones about it, we will be in delivery one day," said Rick. "It's a natural extension… [Blaze Pizza] is much better [than competitors]. What we do is what people want."

In addition to industry-topping domestic growth, Blaze Pizza also seems to be on the cusp of an international expansion push. While Rick Wetzel told Business Insider he could not yet share any international expansion plans, he said that next January he hoped to be discussing the chain's successful year of international growth.

"We knew there was a gaping hole in this category," said Rick.

Rick said he knew that other competitors like Mod Pizza and Chipotle-owned Pizzeria Locale would be quick to emerge. The threat of competition lit a fire under Blaze Pizza's drive to expand, resulting in a business plan created for a 1,000-plus location chain and national distribution plans set in place before the first restaurant even opened.

LeBron James, an original investor in Blaze Pizza, has recently taken a larger role in the company's marketing. Blaze Pizza

As the chain has expanded over the the last five years, Blaze's business model has remained essentially the same.

The chain's bread-and-butter is still personal pizzas, made-to-order in front of customers in open-flame ovens. Blaze Pizza's most famous investor is still LeBron James, who has been with the chain since the beginning and ditched a McDonald's endorsement deal in October 2015 to play a bigger role in the chain's marketing.

The biggest change is the scale at which Blaze Pizza operates.

"It's starting to feel like a grown-up company, leaving that startup phase," Rick said.