Banana Cupcakes with Peanut Butter Frosting

I stumbled across these photos yesterday and realized I never blogged the recipe, shame on me!  These cupcakes are divine -- if you enjoyed peanut butter banana sandwiches growing up you will hands down love this cupcake.

Banana Cupcakes with Peanut Butter Frosting
Makes about 28 cupcakes

Ingredients:

For the cupcakes
3 cups sifted cake flour (not self-rising)
1 1/2 teaspoons baking soda
3/4 teaspoon baking powder
3/4 teaspoon salt
1 teaspoon ground cinnamon
4 very ripe large bananas, mashed (about 2 cups)
3/4 cup buttermilk
1/2 teaspoon pure vanilla extract
3/4 cup (1 1/2 sticks) unsalted butter, room temperature
1 1/2 cups packed light-brown sugar
3 large eggs, room temperature

For the frosting
1 1/3 cups creamy peanut butter (I don't recommend using natural peanut butter for this unless you like the grainy texture)
1 cup (2 sticks) unsalted butter, room temperature
1 1/2 cups powdered sugar (I never sift mine, but you can)

Directions:

Preheat the oven to 350F.  Line standard muffin tins with paper liners.  Whisk together cake flour, baking soda, baking powder, salt, and cinnamon.  In another bowl, whisk together bananas, buttermilk, and vanilla.

With an electric mixer on medium-high speed, cream butter and brown sugar until pale and fluffy.  Add eggs, one at a time, beating until each is incorporated, scraping down sides of bowl as needed.  Reduce speed to low.  Add flour mixture in two batches, alternating with banana mixture, and beating until just combined after each.

Divide batter evenly among lined cups, filling each three-quarters full (I like to use a 1/3 cup measure).  Bake, rotating tins halfway through, until a cake tester inserted in centers comes out clean, about 20 minutes (I always check at around 17 minutes and they are usually done at that time in my oven).  Transfer tins to wire racks to cool completely before removing cupcakes.  Cupcakes can be stored overnight at room temperature, or frozen up to 2 months, in airtight containers.

To make the frosting, cream the peanut butter and butter with an electric mixer on medium-high speed until incorporated and fluffy.  Add powdered sugar 1/2 cup at a time and mix on low speed until incorporated some, then mix on high speed until fully incorporated and fluffy.  Repeat with remaining powdered sugar.

To finish the cupcakes I like to pipe the peanut butter frosting on top and drizzle with some Hershey's chocolate syrup.  I was planning to make my own chocolate syrup for this batch, but totally ran out of time and had the Hershey's on hand.

Source: cupcakes adapted from Martha Stewart Cupcakes; I found the frosting recipe on the Internet last year, but forgot to document the source