Step 1: Preheat your oven to 350°F (175°C) and grease and flour a 9x13 inch baking pan or two 8 or 9-inch round cake pans.
Step 2: In a medium bowl, whisk together the flour, baking soda, salt, and cinnamon. Set aside.
Step 3: In a large bowl, using an electric mixer, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Step 4: Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract and mashed bananas.
Step 5: Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix.
Step 6: Pour the batter into the prepared baking pan and spread evenly.
Step 7: Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean. If using round pans, baking time may vary slightly (25-30 minutes).
Step 8: Let the cake cool in the pan for 10-15 minutes before inverting it onto a wire rack to cool completely.
Step 9: While the cake cools, prepare the cream cheese frosting. In a large bowl, beat the softened cream cheese and butter together until smooth and creamy.
Step 10: Gradually add the sifted powdered sugar, one cup at a time, mixing until smooth. Beat in the vanilla extract. If the frosting is too thick, add milk one tablespoon at a time until desired consistency is reached.
Step 11: Once the cake is completely cool, spread the cream cheese frosting evenly over the top. Slice and serve.