Preheat oven to 375F,,In mixing bowl cream butter and sugar until fluffy add eggs and beat 2 minutes, add bananas and vanilla and beat another 2 minutes,,combine dry ingredients add to creamed mixture alternately with buttermilk mix well..stir in pecans..pour into 2 greased and floured 9 inch cake pans, sprinkle each cake with the coconut bake for 25 to 30 minutes or until cake tests done. loosley cover with foil during the last 10 minutes of baking..cool in pans 15 minutes before removing to wire rack coconut side up.
In mixing bowl cream butter add remaining frosting ingredients, beat on low until combined,then beat on high for 5 minutes.
Place one cake layer coconut side down, spread with some frosting add the other cake layer on top with coconut right side up . frost sides and only 1 inch around the top of cake leaving rest of cake top center showing the coconut. cover left over cake with saran and keep in the refrigerator if not all eaten.