Vrbnik has a small handful of restaurants, mostly serving Dalmatian-style seafood with local Žlahtina wine. The best approach is to walk the old town, look at menus, and choose based on what looks freshest that day. Lamb and seafood are the reliable choices; the local lamb from Krk Island has a distinctive flavour from grazing on aromatic herbs.
Eating on a terrace with a view of the channel is the experience worth seeking. It may not be the cheapest lunch you have eaten in Croatia, but the setting earns its premium.