Dry-roast flaked almonds in a pan over medium heat until golden, tossing to prevent burning. Transfer to a plate to cool.
Cut pineapples, including crown, in half lengthwise. Remove flesh with a sharp knife, leaving a rim 2 cm thick. Discard woody core and cut flesh into small pieces.
Segment the oranges and cut into pieces. Slice the bananas and drizzle them with lemon juice to prevent browning. Combine all the fruit in a bowl.
Whisk the orange juice, maple syrup and rum and stir the dressing into the salad. Place the pineapple halves on dessert plates and fill with fruit salad. Drizzle with chocolate topping and sprinkle roasted flaked almonds on top.