Preheat oven to 375 degrees and line a baking sheet with parchment paper. In a large bowl, whisk the flour, sugar, baking powder and salt. Blend the cubed butter into the flour mixture with a pastry blender or fingertips until coarse crumbs form. In a small bowl combine the milk or cream, egg and vanilla. Add liquid mixture to flour mixture and stir just until combined.

Transfer to a lightly floured surface and knead the dough gently a few times. Pat into a 7 inch round and cut the dough with a 2-inch round cookie or biscuit cutter. Spread the rounds evenly on the prepared baking sheet. Brush the tops of the scones with cream or milk.

While biscuits are baking, caramelize the bananas and make the whipped cocoa creme fraiche. In a large fry pan over medium-high heat, melt the butter. Add the banana slices and cook, turning them occasionally with a rubber spatula until they begin to brown, about 2 to 3 minutes. Sprinkle in the brown sugar and continue cooking for another minute. Stir in the rum and cook until the liquid has reduced slightly, about 1 minute.

Combine the creme fraiche, heavy cream, cocoa powder and confectioner's sugar in a bowl. Whip using an electric whisk or mixer until stiff peaks form.

To assemble, divide the caramelized bananas between small bowls or ramekins. Top with biscuits and dollops of cocoa creme fraiche and dust the top of each dessert with ground cinnamon.