Excellent news: Shake Shack’s Chick’n Shack, which the company has been testing in Brooklyn, will be offered at almost all American Shake Shack locations, starting today. (The JFK airport and stadium outposts are excluded, and the Theater District one needs a bit more time.) The sandwich’s cage-free chicken breast gets slow-cooked in buttermilk, hand-dipped into housemade batter, bathed in flour, and fried, and it’s topped with lettuce, pickles, buttermilk-herb mayo, and, of course, a potato roll. Another first: Louisiana hot sauce will now be available, too. Plan lunch accordingly.