Utterly transformed from when the bi-level space housed Union Square Café, TsuruTonTan is a lustrous tavern dedicated to udon noodles. This is the first American outpost of a Japanese chain, with an intimate bar, counter seating and a sunken dining room. Soft yet chewy noodles are made in-house, a blank canvas to soak up uni dashi broth, for instance, topped with a cluster of briny uni, shiso and nori. (That particular dish is served chilled and is delicious in any season.) Oversize ceramic bowls and giant spoons lend drama, as does the wide-ranging, illustrated menu. Top sellers are flagged, a helpful guide.