For the banana sauce, first sauté the finely chopped onion in a little oil until translucent.
Meanwhile, peel the ginger root and cut into small pieces. Mash the bananas or cut them into small pieces. Add the ginger root, bananas and salt to the onions and sauté briefly. Add salt. Deglaze with white wine and simmer a little. Let cool and puree the banana sauce with a hand blender.