For Rum Cream: ============== In the top of a double boiler, blend the egg yolks and sugar. Place this over boiling water and whisk until warm to the touch. Add the butter, 1 or 2 pieces at a time. When all of the butter has been incorporated, whisk until lightly thickened, 1 or 2 minutes longer. Remove from heat and cool, whisking occasionally. When cool, gradually whisk in the rum and fold in about 1/3 cup of whipped cream. Cut off the base and stem of the pineapple, reserving a few small leaves for garnish. Quarter the pineapple lengthwise and then remove the skin and core with a sharp knife. Slice each quarter lengthwise into 1/4-inch-thick slices. To Assemble: ============ Arrange the pineapple slices on chilled plates, overlapping slightly. Gently curl the cantaloupe slices in the shape of an "S" and place 2 pieces on each plate as garnish. Garnish with reserved pineapple leaves. Spoon some of the rum cream over the pineapple and serve remainder of the cream on the side.