The best is Kelly's Ice House for sure! Its an ice cream place, they also offer other foods, such as pancakes, to enjoy. You might want to eat your food sitting on one of the tables outside so you can fully enjoy the beautiful weather!
Mouse Island (Pontikonisi) is only a five-minute boat ride away from Corfu is amazing!! It is said have the remains of Odysseus’s ship after Poseidon turned it to stone. The beaches are stunning and there is a great view of Kanoni across the water. There is also a Byzantine chapel of Pantokrator and may have served as the inspiration for the famous painting Isle of the Dead.