Besalú is overwhelmingly a daytime destination — most visitors are day-trippers, and the evening scene is limited. What the town does well is the morning café stop: coffee and something to eat before the tour groups arrive, when the streets are quiet and the bridge is yours.
A handful of cafés cluster around the main square and along the main street. The evening options are thin; if you're staying overnight, the restaurants are your best bet for a drink after dinner.