If the flavor of pineapple and coconut is a favorite, you'll love this frozen tribute to the piña colada. But is it gelato, as the name says? Well, it's made with gelato-type ingredients: milk rather than cream, with egg yolks for richness. But without a special gelato maker to create that Italian confection's thick, dense, smooth texture, we're not sure we can call this gelato. Still, it's supremely tasty — especially with the addition of the optional rum.