Method
Prepare the Oven and Pan
Preheat your oven to 350°F (175°C). This ensures the cake bakes evenly.
Grease and flour a 9x13 inch baking pan to prevent sticking.
Make the Cake Batter
In a large mixing bowl, whisk together the flour, baking powder, baking soda, and salt. This helps to evenly distribute the leavening agents.
In another bowl, cream the softened butter and granulated sugar using an electric mixer until light and fluffy, about 3-4 minutes.
Add the mashed bananas, eggs, sour cream, and vanilla extract to the butter mixture. Mix until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Do not overmix to keep the cake tender.
Prepare the Cream Cheese Layer
In a medium bowl, beat the softened cream cheese and granulated sugar until smooth.
Add the egg and vanilla extract, mixing until fully incorporated. This layer adds creaminess and richness to the cake.
Assemble the Cake
Pour half of the cake batter into the prepared baking pan, spreading it evenly.
Spoon the cream cheese mixture over the batter, spreading it gently to cover.
Top with the remaining cake batter, spreading it to cover the cream cheese layer.
Add Topping and Bake
In a small bowl, mix together the brown sugar, chopped walnuts, and cinnamon. Sprinkle this mixture evenly over the top of the cake.
Bake in the preheated oven for 40-45 minutes, or until a toothpick inserted in the center comes out clean.
Cool and Serve
Once baked, remove the cake from the oven and allow it to cool in the pan for 10 minutes.
Transfer the cake to a cooling rack to cool completely before slicing. This helps maintain the cake's texture.
Notes
Store any leftovers in an airtight container at room temperature for up to 3 days or refrigerate for up to a week. This cake can also be frozen for up to 3 months.