Shake Shack, the New York City burger chain, enjoyed a profitable first day, as investors snagged shares on Jan. 30 when it became a publicly traded company. In its initial public offering, shares were priced at $21, but they jumped to nearly $50 as trading began, and closed the day just under $46.

In 2014, Shake Shack opened 10 new company-operated U.S. locations and a dozen new international licensed restaurants. In each new city, it partners with a local bakery to create a signature dessert. The company has reported it could eventually grow to 450 locations.

Shares in the company more than doubled in their first day of trading, valuing what once was a humble hot dog cart in Manhattan’s Madison Square Park at more than $1.6 billion.

By the close of trading, shares of the company, which trade under the symbol SHAK, closed at $45.90 after pricing at $21 the day before.

That public debut — coming off an initial public offering that had already exceeded expectations — revealed a rare level of excitement on Wall Street for the self-described “modern day roadside” burger joint.

Aaron Allen, a consultant, says a revolution is taking place in the restaurant business, according to a report by NPR. People want their food fast, but they don't want fast food. They want to see their food made to order and put together right in front of them.

"If you take Red Lobster and Olive Garden, TGI Fridays, IHOP, Applebee's, Chili's, add them all together and their valuation is less than just Chipotle," Allen says.

Shake Shack hopes to be the Chipotle of burgers, Allen says. But the company already faces much competition from chains such as Five Guys, In-N-Out and Habit Burger. He adds that the so-called fast-casual movement has been very profitable, and it's expected to more than triple its sales within the next decade.

"This sector is actually cannibalizing parts of the industry," Allen says.

Shake Shack recorded about $79 million in sales over the first nine months of 2014. The chain has 63 locations around the world, including restaurants in London and Dubai, though annual sales volume at the chain’s seven Manhattan locations is about 50% higher than at its other locations.

The company, founded in 2004 by restaurateur Danny Meyer, filed for its IPO at the end of December, with the New York Stock Exchange under the symbol “SHAK.”