Peppermint Whoopie Pies

I have never made whoopie pies before.  However, I recently went to a cookie swap that had them and it gave me a hankering.  I found out short notice about a work holiday pot luck, and I had my excuse!

The filling I doubled from the original recipe, and added shortening for half the butter, in order to taste slightly more "oreo-filling"-esque.   A good choice.  I purposely did not double the vanilla.  The peppermint flavor is decidedly there, but not overpowering, so if you want that brrrrrrr feeling you should add another 1/2 tsp.

Peppermint Whoopie Pies
Adapted from Brown Eyed baker (who adapted from Whoopie Pies)
Makes About 24 whoopie pies

For the Cakes:
1 and 2/3 cups all-purpose flour (238 gms)
2/3 cup unsweetened cocoa powder (66 gms)
1½ teaspoons baking soda
½ teaspoon salt
4 tablespoons unsalted butter, at room temperature
4 tablespoons vegetable shortening
1 cup dark brown sugar (192 gms)
1 egg
1 teaspoon vanilla extract
1 cup milk (skim is fine)

For the Filling (Peppermint Buttercream):
4 cups powdered sugar
4 tablespoons unsalted butter, at room temperature
4 tablespoons vegetable shortening
6 tablespoons  heavy cream
2 teaspoons vanilla extract
1 teaspoon peppermint extract
1 teaspoon salt

Crushed candy canes, to garnish as desired.  Since I was making these a day in advance, I thought it was ill advised.

Cake:

Preheat oven to 375 degrees F. Line two baking sheets with parchment paper.

Whisk together the flour, cocoa powder, baking soda, and salt in a medium bowl. In the bowl of a stand mixer fitted with the paddle attachment, beat together the butter, shortening and brown sugar on low speed until just combined. Increase the speed to medium and beat until fluffy and smooth, roughly 3 minutes. Add the egg and vanilla and beat for another 2 minutes.

Add half of the flour mixture and half of the milk to the batter and beat on low until just incorporated. Scrape down the sides of the bowl. Add the remaining flour mixture and ½ cup milk and beat until completely combined.

Drop about 1 tablespoon of batter onto one of the prepared baking sheets and repeat, spacing them at least 3 inches apart. I used my tablespoon cookie scoop.  Bake one sheet at a time for about 10-11 minutes each, or until the whoopie "cakes/pies" spring back when pressed gently.

Remove from the oven and let the cakes cool on the sheet for about 5 minutes before transferring them to a rack to cool fully.

Filling:

In the bowl of a stand mixer fitted with the paddle attachment, beat together the powdered sugar, shortening, and the butter, starting on low and increasing to medium speed, until the mixture is crumbly, about 1 minute. Add the heavy cream, vanilla, peppermint extract, and salt and beat on high until smooth, about 3 minutes.

Assemble the Whoopie Pies: Spread filling onto the flat side of one cake using a knife or spoon, or using a pastry bag and your trusy 1M tip. Top it with another cake, flat-side down. Repeat with the rest of the cakes and filling. Roll the edges in crushed candy canes if you like, but they may soften the candy canes f they are not eaten within a few hours.
You could also roll edges in sprinkles.