An acquaintance who lives on City Island pointed me to Sugar & Spice, a sweet little bakery cafe decorated in kid-fiendly primary colors that also has house-made ice cream.
The ice cream's in the medium butterfat range, and a bit sweet, but is well made, with true flavors. Vanilla has good vanilla bean flavor (and vanilla bean specks throughout), and there were several swirled flavors (mango, passionfruit) based on it; mango swirl had good fresh mango flavor in the swirl.
The only thing I tried from the bakery side was a croissant, which was very good. It had the darker, crisp and shattering crust so lacking in local most examples, and layers of very buttery pastry within (perhaps even a bit too buttery for my own taste, but imbued with the taste of fresh, sweet butter throughout).
There is also a selection of cakes, cookies, and other pastries, as well as espresso. It's not a destination in itself, but if you want a nice snack on City Island, or to pick up something for tomorrow's breakfast, I certainly recommend Sugar & Spice.
Sugar & Spice
536 City Island Avenue
City Island, NY 10464