If you are a fan of banana pudding, you'll love this ethereal mousse. When pureed with Maraschino liqueur or vin Santo, bananas impart wonderful flavor to the usual custard base. Gelatin sheets have the thickening power of powdered gelatin, without any of the graininess that often results. Soak them in cold water for about ten minutes to soften, then wring out the water before mixing with hot liquid to dissolve.