Dulce de Leche Banana Cake

sour cream1 teaspoon baking soda8 tablespoons unsalted butter, softened1 cup sugar2 eggs1 teaspoon vanilla extract2 cups flour1 teaspoon baking powder¼ teaspoon salt1 cup mashed bananas (about  1 ½ large bananas)¾ cup dulce de leche

cream cheese, cold8 tablespoon unsalted butter, softened1 teaspoon vanilla extract2 ½ cups of powdered sugar, sifted