Part 3/5:
Once your bananas are mashed, add the egg to the bowl and whisk them together. For convenience, you can whisk the egg separately, but it's perfectly fine to do it in the same bowl to save on dirty dishes. Next, mix in the sour cream and vanilla extract, followed by the ground cinnamon if you choose to use it.
Step 3: Add the Butter and Sugar
Then, pour in the melted butter and add the brown sugar. Stir well until everything is thoroughly combined.
Step 4: Incorporate the Dry Ingredients
After the wet ingredients are mixed, sift in the cocoa powder, followed by a pinch of salt and the all-purpose flour. Be gentle while mixing; you want to ensure that everything is just combined without overmixing.