Shack Shack on the UES is offering a new burger with bacon and pepper relish. I tried one and was definitely pleased with it. The bacon was good quality and nicely smoky but what I really liked was the pepper relish. It added a really good brightness to cut through the rich bacon cheeseburger and reminded me of a Balkan cherry pepper spread.
I previously had not been a fan of Shake Shack but someone recently turned me on to ordering the burgers rare. Is it worth the wait on line? I hate lines and wouldn't say so but the UES location is quick.