Buns, beef, stars and stripes

For instance, the signature Umaami burger at his restaurant in Hengfeng Road, Shanghai, features not one but two wagyu beef patties that are paired with ingredients made in-house: a sweet and savory onion bacon jam, bacon slices, pickles and an onion brioche.

He also plans to infuse a Southeast Asian twist by replacing the beef patty with a har cheong gai - chicken deep fried in pungent prawn paste - and combining it with an onion brioche, calamansi juice, melted cheddar, cilantro and a spicy and citrusy condiment called sambal belacan that is made from a secret family recipe.

For White Castle, the key to defining itself would be owning the slider category, Poon says.

For Shake Shack, it will be focusing on its mission statement to "stand for something good".

This "goodness" that Shake Shack prides itself has different fronts. The first is about paying forward to the local communities it is in. For example, it will donate 5 percent of sales from its straw-bei li cheesecake to Flying the Hope, a charity in Shanghai that helps children from underprivileged families complete their studies.

The other is related to its commitment to serving hormone- and antibiotic-free beef. In a report last year titled Chain Reaction IV: Burger Edition, Shake Shake was one of only two US burger chains surveyed that received an A grade in this area.

"We want to make sure our beef is raised the right way," Garutti says. "We think that makes a difference. We also believe that it does affect the taste. Every piece of the supply chain matters.

"We want to be a great company for the world. I think that's one of the things that people really connect with it. They want to be a part of something that has an ethos that goes beyond selling hamburgers."