Ingredients:

  • 1/2 cup unsalted butter, softened
  • 1/2 cup vegetable oil
  • 1 1/2 cups granulated sugar
  • 3 large eggs, room temperature
  • 2 tsp pure vanilla extract
  • 1 1/2 cups overripe bananas, mashed
  • 3 cups all-purpose flour
  • 1 tsp baking soda
  • 1 tsp baking powder
  • 1/2 tsp salt
  • 1/2 cup sour cream
  • 8 oz full-fat cream cheese, softened
  • 1/2 cup unsalted butter, softened
  • 4 cups powdered sugar, sifted
  • 1 tsp pure vanilla extract
  • 2 tbsp heavy cream

Instructions:

  1. Preheat oven to 350°F (175°C). Grease a 9x13-inch baking pan with butter or line with parchment paper.
  2. Sift together all-purpose flour, baking soda, baking powder, and salt in a medium bowl; set aside.
  3. In a large bowl, beat softened butter, vegetable oil, and granulated sugar on medium-high until pale and fluffy, approximately 3 minutes.
  4. Add eggs one at a time, beating well after each addition. Stir in vanilla extract and sour cream until the batter is smooth and glossy.
  5. Gradually mix the sifted dry ingredients into the wet batter until just combined.
  6. Gently fold in the mashed overripe bananas by hand to maintain air bubbles and prevent over-mixing.
  7. Pour batter into the prepared pan and bake for 45 minutes or until a toothpick inserted in the center comes out clean.
  8. Allow cake to cool completely on a wire rack.
  9. Prepare frosting by beating softened cream cheese and butter until smooth. Gradually add powdered sugar, vanilla extract, and heavy cream until glossy and stiff peaks form.
  10. Spread frosting evenly over the cooled cake using an offset spatula.