Obviously Italian dishes, like lasagne, spaghetti alla bolognese, gelato italian ice-cream, and whatever you eat in Italy.
Supermarkets in San Marino are few and far-between, although the following can help in this area:
Conad
Azzurro shopping center, v m moretti 23, serravalle sm 03508
Sma Supermercati
Via del passetto 113, fiorentino sm