Preheat your oven to 350°F (175°C) and prepare a 9x13-inch baking dish by greasing it with butter or lining it with parchment paper.

In a stand mixer, combine the softened butter and granulated sugar until light and fluffy, about 3-5 minutes.

Add eggs, full-fat sour cream, and vanilla extract to the mixture, beating until smooth, about 2-3 minutes.

In a separate bowl, whisk together all-purpose flour, baking soda, and salt. Gradually blend into the wet ingredients.

Gently fold in the mashed ripe bananas using a spatula with care not to over-mix.

Pour the batter into the prepared baking dish and bake for 25-35 minutes, or until a toothpick comes out clean.

Cool the cake completely in the pan on a wire rack for at least 30-45 minutes before frosting.

In a mixing bowl, beat softened cream cheese and butter together until smooth and creamy, about 2-3 minutes.

Gradually add powdered sugar and heavy whipping cream to the mixture, beating until thick and fluffy, about 3 more minutes.

Once the cake is completely cooled, frost it with the cream cheese frosting using a spatula.