Preheat oven to 350℉. Spray three 8-inch cake pans with baking nonstick spray. Line the bottoms with a parchment paper circle and spray again.
In a medium bowl, mix the flour, baking powder, baking soda, cinnamon, and salt.
3 cups All-purpose flour, 2 tsp Baking powder, 1/2 tsp Baking soda, 1 tsp Salt, 2 tsp Ground cinnamon
In a separate bowl, mix the melted butter, brown sugar, and sugar. Add in the vanilla, sour cream, milk, and eggs. Mix until combined.
3/4 cup Unsalted butter, 1 cup Brown sugar , 1/2 cup White granulated sugar, 1 tsp Pure vanilla extract, 1/2 cup Sour cream, 1/2 cup Milk, 3 Large eggs
Add in the mashed bananas (make sure they are mashed well!) and mix in. The bananas will make it look lumpy.
3 Bananas
Add in the dry ingredients and mix until combined.
Pour the cake batter evenly between the two cake pans.
Bake for 27-29 minutes. Bake until a toothpick inserted comes out clean.
Let the cakes sit in the hot pans for 10 minutes before transferring to a cooling rack. Cool completely before decorating.