My two favorite mid-priced places are Osteria del Treno (not far from the station, very traditional food, fairly humble dining room, interesting wines, very local ingredients) and Rovello 18 (a bit more upscale, nearer to the Castello, simple and wonderful food, better/deeper wine list).
Edited to add that the most local dish in January/February is Cassoeula, a pork dish:
https://en.wikipedia.org/wiki/Cassoeula