An elegant and easy dessert that you can bang out in under an hour.
Preheat the oven to 400┬░F. In a pot, stir together the sugar, cornstarch, and salt. Add the hot water slowly, whisking constantly. Place the pot over high heat and bring the mixture to a simmer while continuing to whisk. Turn off the heat once the sauce has thickened, 3 to 5 minutes. Add the rum and the vanilla scrapings; stir to incorporate.
Cut the top and bottom off the pineapple with a large sharp knife. Stand the pineapple up on the counter and slice off the rind from top to bottom; then cut it into thirds lengthwise. Cut the wedges in half the short way so you have six thick chunks; remove the cores. Put the pineapple wedges on a nonstick cookie sheet and ladle them with half of the rum sauce. Bake for 30 minutes; then switch the oven to broil and cook until the pineapple is caramelized, 10 to 15 minutes. Serve a hunk of pineapple covered with remaining rum sauce, toasted coconut, and 2 scoops of ice cream.
Edited: October 12th, 2009