DELISH! i halved this recipe and just used 1 stick of butter in the margarine and shortenings place, i used regular JIFF peanut butter, natural peanut butter is too runny. i brought it too a pot luck and everyone LOVED it(used it to frost banana chocolate squares from this site also) its not to sweet even with all that sugar, the peanut butter flavor and bananas really stand out. this recipe is a keeper and definitely adds to any banana recipe!!
I used crunchy peanut butter and butter flavored shortening. I omitted the margarine because of the above substitution. I figured it would have more stability with more shortening. I did a drop or two of butter flavor. It's a little sweet. I am hoping it will not be so sweet once it sits.
Yum, yum, yum! This was a great recipe. I didn't add the butter flavor, since I didn't have any. And I mashed the bananas up and added them to the frosting. Was awesome on a chocolate cake!