Let’s just get this out of the way first: This tiny, homestyle Southern Italian spot on Federal Hill is one of the toughest reservations to nab in town—just keep calling, it’s worth it. The namesake Umberto gregariously hosts while his wife, Lia Bellini, cooks with little more than a couple of induction burners in the cramped open kitchen. Her five-course set menu changes nightly, but always features simply delicious rustic fare, like buffalo mozzarella flown in from a relative’s farm in Italy; polenta with fennel sausage; zucchini fritters with mascarpone and speck; and pasta tossed with chickpeas, olive oil, and Pecorino Romano. By the end of the meal, you’ll be practicing your Italian with your fellow diners sitting elbow-to-elbow in the small space. Mangia!