Danny Meyer’s Shake Shack empire has grown from a niche burger joint to worldwide chain in record time.

On Friday, the company went public, with the price of shares selling for more than double its initial public offering at $21.

Though the chain may be playing with the big burger boys now, Meyer says his company is still committed to growth based on food sustainability and says he'll not compromise on quality ingredients.

Here are some of our favorite things about Shake Shack that we hope will never change.

1. They use humanely raised beef.


(Shake Shack)

Shake Shack burgers may not be low in calories, but the chain is committed to using high quality ingredients across the board. All burgers are made from Angus beef, vegetarian fed with no hormones or antibiotics.

2. They serve breakfast.


(Shake Shack)

There are a lot of people that would probably have Shack Shake for breakfast lunch and dinner if left to their own devices. Travelers in and out of New York City can start their day off with a freshly prepared sausage or bacon sandwich at JFK Airport or Grand Central Terminal. The chain makes their own pork sausage from scratch, and trust us when we say this unlike any breakfast sandwich you’ll find from a typical fast food restaurant.

3. The ever-expansive Custard Calendar.


(Shack Shake)

Super thick milkshake or soft ice cream? It's hard to define, because the Shake Shack Concrete is a creamy treat in a category all its own. While vanilla and chocolate frozen custard are always available, the chain is known for its constantly rotating calendar of Concrete flavors that never disappoint. From Salted Buttery Caramel, to Candy Cane Crunch or Coffee & Donuts, it’s always exciting to see what Meyer’s chefs will come up with next. For picky eaters, at some locations you can even make your own custom Concrete with a variety of mix ins.

4. They have their own beer and wine.


(Shake Shack)

While alcohol isn't served at all Shake Shacks, those that do don't just serve the average Bud Light. Brewed exclusively for the restaurant by Brooklyn Brewery, Shackmeister Ale is a deep golden IPA that's bitter, bright and very versatile. The chain also offers two wine choices: a red blend and a white from Frog's Leap. And the best part is that you can take away a whole bottle if so desired.

5. Their vegetarian burger is actually delicious.


(Shake Shack)

Ok, ok we’re not pretending that Shake Shack’s ‘Shroom burger tastes like meat—and neither do they. That’s why it’s amazing. Instead of using a ton of fillers and bland tofu crumbles, the chain lets the natural flavor of the mushroom do its thing with tons of cheese and their signature ShackSauce. This burger won’t convert die-hard carnivores any time soon, but it’s a delicious alternative to a traditional beef burger any day.