Combine ingredients in a glass filled with ice and stir to serve. If desired, garnish with a pineapple leaf or fruit wedges.
This cocktail is basically a Piña Colada when you don't have any coconut milk, but it is delicious in its own right. Vary the proportion of pineapple juice up to 3:1. Experiment with flavored or spiced rums. For a little more sophistication, try adding a dash of sweet liqueur, such as cherry liqueur or triple sec.