Preheat oven to 350°F/177°C. Grease and line four 6-inch round pans. Set aside.
In a bowl, combine cake mix, eggs, mashed bananas, oil, water, and chocolate chips.
Divide the cake batter even among the prepared pans.
Bake for 20-25 minutes or until cake is set and lightly golden brown.
Prepare peanut butter frosting in a mixer bowl with the whisk attachment. Pour in the cream and whip until it forms soft peaks. Incorporate the peanut butter and powdered sugar. Fold in the gelatin. Set aside.
Prepare filling by placing the peanut butter and cream in a microwave safe bowl. Microwave in 15 second intervals until mixture is smooth. Repeat this step for the chocolate ganache filling.
Level the tops of the cake once they have cooled. Fill the cake layers with peanut butter filling, and then spread with chocolate ganache. Place the cake layers on top of each other. Place a dowel on the center to secure the cake.
Frost the cake with the prepared peanut butter frosting. Use a spoon to add texture the top part of the cake and place chocolate shavings on the bottom part. Serve.