Preheat oven to 350°F (175°C) and grease and line two 9-inch cake pans.
In a medium bowl, whisk together flour, cocoa powder, baking soda, baking powder, and salt.
In a large bowl, beat eggs, sugar, buttermilk, vegetable oil, and vanilla extract, then stir in mashed bananas.
Gradually add dry ingredients to wet ingredients, mixing until combined.
Pour batter evenly into prepared pans and bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
Allow cakes to cool completely before frosting.
To prepare the frosting, beat butter until light and fluffy, then gradually add powdered sugar and cocoa powder.
Add heavy cream, vanilla extract, and a pinch of salt, then beat until smooth and creamy.
Assemble the cake by placing one cake layer on a serving plate and spreading a layer of chocolate frosting.
Add the second cake layer and frost the top and sides evenly.
Garnish with chocolate shavings and banana slices.
Let the cake sit for 30 minutes before slicing for best results.
How to Serve Double Chocolate Banana Layer Cake
Serve this cake with a dollop of whipped cream on the side or alongside a scoop of vanilla ice cream. It’s sure to impress your guests and make for a delightful dessert!