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The fast-expanding company is preparing an initial public offering that could be worth up to $1 billion.
Shake Shack is known for long lines at its 34 locations in New York, New Jersey, Connecticut, Pennsylvania, Florida and Massachusetts. The brand has also been expanding internationally.
Here's why people are so obsessed with the burger chain.
1. Gourmet Burgers
Shake Shack's burgers are more elevated than the offerings at the typical fast food burger chain, thanks to the 100% antibiotic-free Angus beef and buttered buns. Toppings include Applewood-smoked bacon and cherry peppers. This experience aligns with the values of modern consumers, who are demanding better food quality.
2. ShackSauce
Many of Shake Shack's burgers are topped with the signature sauce, which USA Today describes as "a slightly spicy, sweet and sour blend of mayo, ketchup, mustard and spices." Some copycat recipes online also call for blended dill pickles. Regardless of the ingredients, the sauce adds to the unique Shake Shack experience.
3. Crinkle Fries
Shake Shack controversially changed its fries from crinkle cut to traditional hand-cut last year, leading to many customer complaints. Last month, CEO Randy Garutti announced that the brand was going to stick to crinkle fries, which are more popular and easier to prepare.
Many Yelp reviewers recommend adding Shake Shack's homemade cheese sauce to your fries.
4. "Anti-Chain Chain" Image
The New York Times calls Shake Shack the "anti-chain chain," saying that their dedication to quality and customer service bucked stereotypes of traditional fast food.
Shake Shack spends barely any money on marketing, instead focusing on the quality of food. This message has helped Shake Shack stay popular in an era where diners prefer Chipotle to McDonald's.
Shake Shack "disposed of the notion that fast food had to be precooked or even prepared quickly in favor of quality ingredients and customer experience," writes QSR Magazine.
5. Delicious Milkshakes
Shake Shack's signature custard is the base for these frozen treats. Flavors include chocolate, vanilla, peanut butter, strawberry, and some creative specials like Nutella.
Gothamist ranks the black-and-white shake, a combination of chocolate and vanilla, among the best in New York City.
6. Flat-Top Hot Dogs
Shake Shack began as a hot dog stand in New York's Madison Square Park. Many food writers say the hot dogs, which are made of 100% hormone and antibiotic-free beef, are an underrated treat.
"I was never let down by the hot dogs, bought from Chicago's irreplaceable Vienna Beef, which were split down the middle, griddled and laid in a toasted potato bun with or without the classic Chicago garnishes," writes Pete Wells at The New York Times. "Better yet is the Bird Dog, a smoked chicken and apple bratwurst from Usinger's of Milwaukee."
Fried pickles on a hot dog? Oh no, you didn't. Oh yes, we did: http://t.co/PtL7Po8nBQ pic.twitter.com/KDOo62smVd
- SHAKE SHACK (@shakeshack) March 19, 2014
7. Regional Specialties
In addition to its classic menu, Shake Shack also offers special frozen dessert items at different locations.
The chain serves a "Liberty Shell" custard at its Philadelphia location featuring a cannoli shell, strawberry puree, and lemon ricotta. The New Haven location serves a "Skull and Cones Concrete," which is a similar consistency to a Dairy Queen Blizzard with peanut butter, ice cream cone, and chocolate truffle cookie dough blended in.
8. Secret Menu
Shake Shack has a secret menu, which Thrillist successfully tested. Items include a burger topped with bacon and peanut butter, and a grilled cheese made from buns.
Love the Peanut butter bacon burger from @shakeshack secret menu. Awesome! pic.twitter.com/XvkiJFrPJP
- Mike (@MikeCips) August 22, 2014
9. Vegetarian Options
Founder Danny Meyer said the chain was discriminating about its meat-free options.
"It's only going to go on the menu if you would crave it even if you were not a vegetarian," he told Bon Appetit.
Shake Shack is renowned for it's 'Shroom burger, a portobello mushroom stuffed with cheese.
10. Beer and Wine
Shake Shack sells beer and wine, meaning that it can double as a Happy Hour destination.
Selling alcohol is becoming popular among fast-casual chains who want to find another way to draw in consumers.
The beer is aimed toward craft enthusiasts, and includes a special collaboration with the Brooklyn Brewery.
11. Customer Service
" Unlike the workers at most fast-food outlets, Shake Shack employees give the impression that they truly like their customers," writes Wells at The New York Times.
Shake Shack pays workers a average hourly wage of $10.70, and offers health benefits and paid time off.
Company executives say these policies help them attract better talent, and turnover is lower than industry averages.