Interesting location. You'll see double black doors with the peach logo on the door across from the Shangri-La Hotel doors. Walk in and it'll be the Noodle Bar. Go into the Noodle Bar, take the stairs, and you'll see a weird fridge walk-in awkwardly (yet still trendy) placed in between two bathrooms. Welcome to Momofuku Milk Bar.
Take your pick of what items you want and take it back downstairs to the Noodle Bar for checkout. If you want soft serve, you'll find that by the hostess podium downstairs as well. We went during the afternoon, so no issues, but I wouldn't want to make a trip to the Milk Bar and try to checkout during normal lunch/dinner hours when I'm sure it's packed and the staff is busy.
Just got a crack pie today. $6 for the tiniest, most basic looking slice you've ever seen. It's still really tasty though. There's absolutely nothing special about it and no toppings or anything in it. It's a nice piece of caramel-like, sticky, sugary butter on a thin piece of crust. Soft and gooey on top and sticky and chewy on the bottom. We devoured it in a few bites while standing outside.
I had the compost cookie years ago in the NYC location. Didn't get it this time, but I would still recommend it.