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

In a medium bowl, whisk together the flour, baking soda, salt, and cinnamon; set aside.

In a large bowl, cream together the softened butter and granulated sugar until light and fluffy. Beat in the eggs one at a time, then stir in the mashed ripe bananas.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Stir in the buttermilk and vanilla extract.

Divide the batter evenly between the prepared cake pans and bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.

Let the cakes cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely.

In a large bowl, beat the softened cream cheese and butter with an electric mixer until smooth and creamy.

Gradually add the powdered sugar, one cup at a time, beating until fully incorporated and fluffy. Stir in the vanilla extract.

If the frosting is too thick, add milk one tablespoon at a time until you reach your desired consistency.

Once the cake layers are completely cool, spread a layer of cream cheese frosting over the top of one cake layer. Place the second cake layer on top and cover the entire cake with the remaining frosting.