Sales at a Shake Shack Korea store are the highest of any store worldwide.

Just seven months after the chain launched in Korea, Shake Shack’s 13th international market, the Gangnam branch has outstripped some 120 branches outside the US. It sells 3000 to 3500 burgers a day, according to the Union Square Hospitality Group (USHG), the Shake Shack franchisor.

Also known as the maker of the “New York burger,” the fast casual restaurant started out as a food cart inside Madison Square Park in 2001, expanding its menu from New York-style hotdogs to hamburgers and milkshakes.

It made a foray into the South Korean market last year through an exclusive partnership contract with SPC Group, South Korea’s major food manufacturer and distributor.

Another branch in Chungdam, southern Seoul, has also made it to one of the top three in terms of sales.

A third shop is scheduled to open in April in Dongdaemun, a busy shopping district.

• Original reporting by Yonhap, via Korea Bizwire.