Not content with merely being named the best pizza in Lower Manhattan by the 5 Boro Pizza Tour, L’asso has installed a head chef, Daniel Riviera, in its basement kitchen with the aim of introducing a menu that goes beyond pies and pasta. Riviera — who is Puerto Rican — has been bumping around kitchens in New York and New Jersey since graduating from the New York Art Institute with a degree in culinary arts. A month into his tenure, he’s added one dish to the dinner menu: a skirt steak marinated in primitivo, then grilled and topped with a chimichurri sauce. For $15, it’s served with an arugula salad of shaved Parmesan and aged balsamic. By December, there’ll be five more entrées, including a fish dish and a linguine with littleneck clams, as well as an expanded brunch menu. L’asso isn’t really hurting for customers, but this should help it hold its own against a trio of ambitious newcomers in its immediate vicinity — the Mott, Civetta, and Travertine.