adapted from Gourmet Magazine, 1968
Blend pineapple, coconut milk, lime juice, and sugar, until it is a thick puree. Strain (if desired; I probably did not).
Chill the juice and return it to the blender, with 1 1/4 cups firmly packed finely crushed ice and 2 ounces light rum. Blend the mixture at high speed for about 30 seconds, or just until it is the consistency of soft sherbet. Pour the drink into a highball glass and decorate it with a stick of fresh pineapple and a green maraschino cherry. Serve the drink with a straw. The rum may be omitted, if desired."
Blend together strained juice (or puree) with ice and rum.