While in Portofino, the best thing to do is to enjoy a beautiful gelato. Make sure to go to Gelateria Gepi to enjoy a delicious gelato! It's relatively affordable for Portofino's standards, but trust me the gelato was so good I was about to buy a second one after I finished my gelato (this doesn't happen often ahah).
There's also another gelateria, but their gelato looked artificial and was more expensive. Come here and enjoy!