Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the eggs, mashed bananas, and vanilla extract, and mix until well combined.

In another bowl, whisk together the flour, baking soda, and salt.

Gradually add the dry ingredients to the wet mixture, alternating with the buttermilk, and mix until just combined.

Divide the batter evenly between the prepared cake pans.

Bake for 25-30 minutes or until a toothpick inserted into the center comes out clean.

Let the cakes cool in the pans for 10 minutes, then transfer to wire racks to cool completely.

In a mixing bowl, beat the softened cream cheese and butter together until smooth.

Gradually add the powdered sugar and vanilla extract, and mix until creamy and well combined.

Once the cakes are completely cooled, spread a layer of frosting on top of one cake layer, then place the second layer on top and frost the top and sides of the cake.

Decorate as desired and serve.