Chocolate Banana Cupcakes with PB Brown Sugar Buttercream

This cupcake is from Joy of Baking and is an delicious cupcake.  Perfect texture and just very tasty.  I completely screwed up the original recipe for the icing by adding too much peanut butter, so I had to fix it, so I can not tell you how the icing is.  While mine is still a bit too peanut buttery, it is very good.  I am sure the original recipe is excellent.  Sorry.
The combo of peanut butter frosting with this cupcake is very good though.  I could easily eat it with chocolate icing or no icing at all which is strange for me because I am an icing kind of girl.  But this is just an excellent cupcake.  Original recipe came from:
http://tidymom.net/2011/banana-buster-brown-cupcakes/

BANANA CHOCOLATE CUPCAKES 

by Joy of Baking

INGREDIENTS:

• 1 cup granulated white sugar
• 1 scant cup all-purpose flour
• 3/8 cup unsweetened cocoa powder (little more than 1/3 cup)
• 3/4 teaspoon baking powder
• 3/4 teaspoon baking soda
• 1/4 teaspoon salt
• 1 large egg
• 1/2 cup mashed ripe bananas (about 1 medium sized banana)
• 1/2 cup warm water
• 1/4 cup milk
• 1/4 cup canola or corn oil
• 3/4 teaspoon pure vanilla extract

DIRECTIONS:

Preheat oven to 350° and line muffin pan with 12 cupcake liners.  Using a large bowl, whisk together dry ingredients: sugar, flour, cocoa powder, baking powder, baking soda and salt. Set asideIn another large bowl, whisk remaining ingredients until combined: egg, banana, water, milk, oil, vanilla.Combine wet and dry ingredients and stir until combined.Scoop batter into cupcake liners 3/4 full.Bake for 20 minuets or until toothpick inserted comes out clean.Remove from oven. Cool completely before frosting.

Peanut Butter Brown Sugar Buttercream

Ingredients

• 2 large egg whites
• 1/2 cup packed light brown sugar
• 1/8 teaspoon salt
• 1/4 cup peanut butter
• 1/2 cup (1 stick) unsalted butter, softened

Instructions

In a heat proof bowl, whisk together egg whites, sugar and salt. Place over (not in) a pan of simmering water. Cook, whisking continuously until sugar is dissolved and warm to the touch.  Pour mixture into bowl of electric mixer. Beat on medium speed until fluffy, approximately 15 minutes.  Raise speed to high, and mix until stiff peaks form (this took about 7 minutes).  Reduce speed to medium-low and add peanut butter a little at a time, then butter, 1 tablespoon as a time until fully mixed.  Pipe onto cupcakes.