Preheat your oven to 350°F (175°C). Grease and lightly flour a 9x13-inch baking pan.

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

In a large bowl, cream the softened butter with granulated and brown sugar until light and fluffy.

Add eggs one at a time, beating well after each addition, followed by the vanilla extract.

Gradually mix in the mashed bananas.

Alternate adding the flour mixture and buttermilk to the banana mixture, starting and ending with the dry ingredients. Mix until just combined.

Pour the batter into the prepared baking pan and smooth the top.

Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean. Let the cake cool completely in the pan before frosting.

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

Gradually add the powdered sugar, one cup at a time, beating until fluffy and smooth. Mix in the vanilla extract. If the frosting is too thick, add heavy cream 1 tablespoon at a time to reach the desired consistency.

Once the cake is completely cool, generously spread the cream cheese frosting over the top. Optionally, garnish with chopped walnuts, pecans, or a dusting of cinnamon.