Name: Chocolate-Peppermint Whoopie Pies
Cook time: P0Y0M0DT0H45M0.000S
Total time: P0Y0M0DT1H30M0.000S
Yield: about 6 large or 16 small whoopie pies
Ingredients: 2 cups all-purpose flour; 1/2 cup Dutch-process cocoa powder (I use Hershey’s Special Dark); 1 1/2 teaspoons baking soda; 1/2 teaspoon kosher salt; 1/2 cup (1 stick) unsalted butter, at room temperature; 1 cup granulated sugar; 1 large egg, at room temperature; 1 teaspoon pure vanilla extract; 1/2 cup buttermilk, at room temperature; 1/2 cup brewed coffee; 1 cup (2 sticks) unsalted butter, at room temperature; 4 cups powdered sugar, plus more as needed and for dusting the tops; 2 to 4 tablespoons milk; 1 teaspoon peppermint extract; 2 small pinches of kosher salt; Red food coloring, for making the striped filling; Crushed candy canes or peppermint candies (about 9 starlight mints), for decorating

Directions

Special equipment:

a small cookie scoop; a piping bag with a star tip, optional

Prepare the Chocolate Whoopie Pies: Preheat the oven to 350 degrees F and line two baking sheets with parchment paper.
In a medium bowl, whisk together the flour, cocoa powder, baking soda and salt. Set aside.
In a large mixing bowl, cream together the butter and granulated sugar until light and fluffy, 2 to 3 minutes. Add the egg and vanilla extract to the butter-sugar mixture and mix until well combined. Gradually add the dry ingredients, buttermilk and coffee to the creamed butter mixture, alternating with the buttermilk and coffee and beginning and ending with the dry ingredients. Mix on medium until just combined. Don’t forget to scrape the bowl!
Form the Whoopie Pies: Using a cookie scoop or a spoon, drop equal portions of batter onto the prepared baking sheets, spacing them about 2 inches apart. You should have about 6 large or 16 small whoopie pie halves on each sheet, depending on the size of your scoop. Using the back of a spoon or your fingers, shape each portion into a round disc, if necessary. 
Bake and Cool: Bake the whoopie pie halves for 10 to 12 minutes or until they spring back when lightly touched. The smaller your scoop, the less time they’ll need to bake. The bigger your scoop…you get the idea. Allow them to cool on the baking sheets for a few minutes before gently transferring them to a wire rack to cool completely.
Prepare the Peppermint Filling: In a mixing bowl, beat the butter until creamy. Gradually add the powdered sugar, milk, peppermint extract and salt. Beat until smooth and fluffy. Adjust the consistency by adding more milk or powdered sugar as needed.
To make the striped peppermint filling (see Cook's Note): Prepare a 12-inch-long piece of plastic wrap.
Using two-thirds of the peppermint filling, create 2 parallel lines of white filling along the long side of the plastic wrap. In a separate bowl, tint the remaining third of the peppermint filling with 3 to 5 drops of red food coloring. Remember – a little goes a long way! Place the red filling in between the 2 white lines, resembling a hot dog with white buns and a red center. Carefully wrap the plastic wrap around the filling to form a log. Trim the end of the plastic wrap log and load it into a piping bag fitted with a star tip.
Assemble the Whoopie Pies: Once the whoopie pie halves are completely cool, pipe the striped peppermint filling on the flat side of one whoopie pie half. Top with another whoopie pie half, flat-side down, to create a sandwich.
Decorate: Roll the edges of the whoopie pies in crushed candy canes or peppermint candies for a festive touch. Lightly dust the top of the whoopie pies with powdered sugar.
Serve and enjoy: These moist and decadent chocolate peppermint whoopie pies are now ready to be enjoyed. Serve them at your holiday gatherings or as a special treat for your loved ones. These are my daughter's favorite!

Cook’s Note

To fill and assemble the whoopie pies without piping, you can skip the steps for creating the striped peppermint filling. Spread a small amount of the white peppermint filling on the flat side of one whoopie pie half, then top with another whoopie pie half flat-side down.