For optimal flavor and texture, choose ripe bananas that have a few brown spots on their peel. Their natural sweetness and intensified banana flavor make them perfect for baking. If you'd like to get a head start, you can bake the cake layers a day in advance—just wrap them tightly in plastic wrap and keep them at room temperature. To maintain the cake’s freshness and avoid sogginess, it's best to assemble it with the banana cream filling and frosting on the day you plan to serve it.