Up a flight of stairs and down a small hallway, Lazzara’s isn’t easy to find. But perseverance pays off for Garment District savants who’ve made it their hangout since 1985, when brothers Tony and Sebastian Lazzara first opened. The dining room plays up a 19th-century feel, with original tin ceilings, rust-hued exposed-brick walls, beige tile floors, and sconces that evoke antique gas lamps. But the main attraction here is the exceptionally thin and crispy Sicilian-style square pizza — usually a thick-crust affair — topped with tangy tomato sauce and gooey melted mozzarella. More than a dozen signature pies are on offer, like Lazzara’s Special, topped with salty slices of prosciutto, earthy black olives, and sweet sun-dried tomatoes, or Sebastian’s Seafood with garlic-drenched baby shrimp, clams, and calamari. About two-dozen sundry toppings can be ordered in any configuration. Pastas lean toward old favorites like baked ravioli marinara, linguini carbonara, and penne with pesto sauce.