A small, cluttered, perpetually busy pintxo bar on Cuesta de San Francisco that does some of the best classical pintxos in town: gilda (anchovy, olive, pickled pepper on a stick), tortilla, txampi (mushroom on bread with garlic), Iberian ham. Nothing fancy, everything sharp.
Stand at the bar, watch the bartender circulate plates of fresh pintxos every fifteen minutes, and grab what looks good. Cuesta de San Francisco, 3.