01 -
Preheat oven to 350°F (175°C). Spray a 9x13-inch baking dish with cooking spray and set aside.
02 -
In a large bowl, using a hand mixer or stand mixer with a paddle attachment, cream together butter and sugar until light and fluffy. Beat the mixture for a couple of minutes to achieve the desired texture.
03 -
Mix in the eggs, sour cream, and vanilla extract until well combined and creamy.
04 -
Gradually add flour, baking soda, and salt to the wet mixture. Blend on low speed just until combined.
05 -
Gently fold in the mashed bananas until evenly incorporated. Transfer the batter to the prepared baking dish and spread evenly.
06 -
Bake for 25-35 minutes, or until a toothpick inserted in the center comes out clean or with moist crumbs. The edges and top should be light golden brown. Allow the cake to cool completely before frosting.
07 -
In a large mixing bowl, beat together softened butter and cream cheese until smooth. Add vanilla extract, powdered sugar, and heavy whipping cream. Beat on low speed initially, then increase speed until the frosting is thick and smooth. Adjust consistency by adding more powdered sugar or cream if necessary.
08 -
Once the cake is completely cooled, spread the frosting evenly over the top. Optionally, garnish with banana slices and chopped walnuts before serving.
09 -
Cover the frosted cake tightly with foil. Serve immediately or refrigerate for a few hours before serving. Cake can also be made a day ahead and frosted before serving.