- In a bowl, combine the flour, cocoa and salt.
- In another bowl, cream the butter with the icing sugar. Stir in the egg yolks.
- With a wooden spoon, stir in the dry ingredients gently until the dough is smooth. Shape the dough into 4 balls with your hands. Cover with plastic wrap and refrigerate for 30 minutes.
- Meanwhile, in a saucepan, bring the maple syrup to a boil. Cook until a candy thermometer reads 120 °C (248 °F).
- Add the butter, puréed banana, rum and vanilla. Cook for 2 minutes, whisking constantly. Remove from the heat and let cool.
- With the rack in the middle position, preheat the oven to 180 °C (350 °F).
- Roll out the dough to 3-mm (1/8-inch) thick and line four 10-cm (4-inch) tart pans with removable bottoms. Refrigerate the dough for 10 minutes before baking for 8 to 10 minutes. Remove from the oven and allow to cool.
- In a bowl, gently combine the cooled filling with the sliced bananas. Pour into the tart crusts. Refrigerate for at least 30 minutes and serve with whipped cream.