That should sum up how I feel about the Shake Shack Coffee & Donuts custard, but I suppose I should elaborate a little, huh? This is coffee custard with PIECES OF DONUTS MIXED IN people! SERIOUS SERIOUS stuff. SO SERIOUS THESE CAPS ARE NECESSARY. It's usually offered a few times a year (I think) as a monthly special, so if you're anywhere near a Shake Shack when it's available, RUN don't walk and get yourself a cup!