Preheat oven to 375 degrees F. In an ovenproof saucepan or deep skillet, combine sugar with 1/4 cup water and bring to a boil, stirring, over medium heat. Cook, stirring often with wooden spoon until sugar turns to a nutty brown caramel, 12 to 15 minutes. Remove pan from heat and carefully stir in cream, rum, spices and raisins (mixture will bubble furiously). Return pan to heat and boil 3 minutes. Peel bananas, slice them on the diagonal, and add to caramel sauce, turning to coat thoroughly. Transfer pan to oven and bake 3 minutes. Remove from oven and let cool.
Immediately before serving, fill tart shell with pastry cream until three-quarters full, and smooth top. Arrange cooled bananas in a decorative pattern over top of tart; drizzle with a few spoonfuls of raisin-caramel mixture. Pipe whipped cream in decorative rosettes on top of tart and garnish with mint sprigs and confectioners' sugar.
Yield: 8 to 10 servings