There was one lonely and ripe banana in the kitchen. What to do? Bake something, of course. A recipe for peanut butter muffins in my quick bread recipe files served as the inspiration for these moist, lovely and fast-made muffins. I highly recommend.
In the “old days,” the peanut butter was mixed with the dry ingredients in the same manner as shortening or butter. I didn’t bother doing that, just smashed the banana and the peanut butter together on a plate, then added them to the other wet ingredients. I used half all-purpose flour and half of my favorite whole wheat flour, the Bluebird Grain Farms Pasayten hard white. A little handful of mini semi-sweet chocolate chips went into the dry ingredients, a little optional spike, just like the bit of peanut butter icing drizzle.
I don’t share my original recipes for the items which are intended for retail, but muffins aren’t among those, so you can see it here. I used a lightly oiled, non-stick muffin tin. Bake 20 minutes at 400. Wait 5 minutes to remove them from the tin and drizzle a bit of peanut butter icing over them while warm, if desired. Makes 12.
Here it is, bigger. 
Ms Chef in Seattle 