Antica Trattoria Papei
This place, which has been in the Papei family for three generations, attracts both locals and visitors with basic but fine Sienese specialties and reasonable prices. Tucked away behind the Palazzo Pubblico in a square that serves as a parking lot for most of the day, the restaurant's location isn't great, but the food is; thanks to portable heaters, there is outdoor seating all year-round.