Prepare the Pans: Preheat the oven to 350°F (175°C). Line the bottoms and sides of three 8-inch (20 cm) springform pans with parchment paper, then set the prepared pans aside.
Mix the Banana Batter: Place the eggs, packed light brown sugar, vegetable oil, mashed bananas, and vanilla extract in a large mixing bowl. Using a handheld or stand mixer fitted with a paddle attachment, mix on medium speed for about 2 minutes, or until the mixture is smooth and thoroughly combined. Add the Dry Ingredients: Add the flour, baking powder, salt, and cinnamon to the banana mixture. Stir just until the ingredients are combined, taking care not to mix beyond this point.
Fill the Pans: Divide the batter evenly among the three prepared 8-inch pans, spreading it evenly in each pan.
Bake the Cake Layers: Bake at 350°F (175°C) for about 16–18 minutes, or until a toothpick inserted into the center of a cake layer comes out clean.
Cool the Layers: Remove the baked cake layers from the oven and allow them to cool completely to room temperature before assembling the cake.
Whip the Frosting Base: Add the room-temperature butter, softened cream cheese, and vanilla extract to a large mixing bowl. Using a handheld or stand mixer fitted with a paddle attachment, mix on medium speed for about 2–3 minutes, until the mixture becomes creamy. Finish the Frosting: Sift the powdered sugar and cocoa powder into the butter and cream cheese mixture, then stir until everything is well incorporated and creamy. Add a pinch of salt to taste and stir to combine.
Adjust the Consistency: If the frosting is too firm, add milk 1 tablespoon at a time until it reaches a smooth, creamy consistency. If it becomes too soft, add additional powdered sugar as needed.
Level the Cake Layers: Once the cake layers are completely cool, use a knife to remove a thin layer from the tops if necessary, creating flat, even surfaces for stacking.
Build the Cake: Place one cake layer on a cake stand, cake turner, or serving plate. Spread one-third of the frosting evenly over the top. Add the second cake layer and repeat with another one-third of the frosting.
Complete the Layers: Place the final cake layer on top, then use the remaining frosting to lightly cover the top and sides of the cake, keeping the intentionally lightly frosted, naked-cake appearance.
Chill the Cake: Refrigerate the assembled cake for 4 hours or overnight before serving, allowing the layers and frosting to set.
Store Leftovers: Keep any leftover cake in an airtight container in the refrigerator for up to 3 days.
