Cook and caramelize pineapples in non-stick pan until softened. Add rum and cook off alcohol.
Pulse almonds, light brown sugar, cinnamon, ginger, flour, and butter in food processor. Fill 5-inch round gratin dishes with cooked pineapple and top with crisp mixture. Cook in a preheated 400-degree oven until brown and bubbly on top, about 10 to 12 minutes.