A wood-and-marble grocer's on Via di Città , in business since 1879. The selection runs to local cheeses (mostly pecorino from the Crete Senesi), oils, preserves, panforte and ricciarelli from the city's best producers, and a small but serious wine cellar.
A good place to buy something to carry home, and one of the few historic shops on the street that still feels mostly used by Sienese rather than tourists.