1Preheat oven to 400 degrees F (200 degrees C). Brush 4 1-cup souffle dishes with melted butter; sprinkle the insides of the cups with sugar.
2Set the egg yolks aside, and place the 4 egg whites into the work bowl of an electric mixer. Beat the egg whites and salt until the whites form soft peaks.
3Place the 2 egg yolks, bananas, honey, vanilla extract, and ginger into a blender; pulse until smooth.
4Scoop the banana mixture into a bowl; use a rubber spatula or wire whisk to gently fold 1/4 of the beaten egg whites into the banana mixture. Gently run the spatula through the center of the bowl, then around the sides of the bowl, repeating until fully incorporated. Fold in the remaining egg whites, being careful to keep as much air in the mixture as possible.
5Spoon the souffle mixture into the prepared dishes; bake in the preheated oven until the souffles have puffed up above the baking dishes and the tops are browned, about 15 minutes. Sift a little sweetened cocoa powder over each souffle for garnish to serve.