Grease two gratin dishes lightly with butter. Cut the bananas diagonally into long slices and distribute them in the molds. Drizzle with orange liqueur and lemon juice.
Spread the creme fraiche in small flakes on the bananas.
Bake in a very hot oven (approx. 250 °) or under the grill for 10 minutes. Pour the almonds on top and dust with powdered sugar.