Preheat oven to 350 degrees. In a large mixing bowl, cream butter, sugar, and brown sugar for 5 minutes or until light and fluffy.
Add eggs one at a time, mixing in between. Stir in vanilla. In small bowl, mash bananas with lemon juice. Add bananas to bowl and mix well. Stir in buttermilk.
Add flour, baking soda, baking powder, and salt. Fold in mini-chocolate chips. Pour into greased baking pans. Use your favorite non-stick cooking spray or butter and then a light dusting of flour. I suggest using three 8-inch cake pans or two 9-inch cake pans.
Bake for 22-26 minutes or until the center of the cake is completely baked.
Let cool and then remove from pans.
In a large mixing bowl, cream together butter and nutella. Add powdered sugar and whip until light and fluffy. Add cream as needed.
Frost cooled layers with Nutella frosting. If you want more Nutella flavoring, drizzle some all over the top of the cake or sprinkle with chocolate shavings.