Preheat your oven to 350°F and grease two 8-inch round cake pans.
In a large bowl, mix flour, baking powder, baking soda, and salt.
In a separate bowl, beat together butter, sugar, eggs, and vanilla until smooth.
Add mashed bananas and brewed coffee to the wet ingredients.
Slowly add the dry ingredients to the wet ingredients and mix until smooth.
Divide the batter evenly between the pans.
Bake for 30 minutes or until a toothpick comes out clean.
Cool the cakes on a wire rack for 10 minutes, then remove from pans.
For the frosting, beat together softened butter, powdered sugar, brewed coffee, and vanilla until smooth.
Frost the cooled cakes and stack them.
Slice, serve, and savor your daring creation.