Last week I stopped by the library to pick up a book I'd requested that had recently come in (this one, if you're curious). I was running a ton of errands that day so the plan was a quick hit and run to grab the book - no stopping to browse the shelves for other cookbooks. It should have been easy enough, the circulation desk is right at the entrance while the cookbooks are up on the second floor; I wouldn't even have to walk past them! You all know where this is going. I wound up spending 15 minutes combing the shelves and then another few trying to convince myself I really didn't need to bring home five more cookbooks no matter how awesome they all looked.
One of my best finds that day? Another whoopie pie book, one I hadn't previously seen anywhere! I'm only a little bit obsessed with whoopie pies, and since it's been over 2 months since my last batch, I was itching to try another.
As flavor combinations go, chocolate and mint is right up there for me with peanut butter and chocolate, so I was instantly drawn to the chocolate mint cookies I found while flipping through the book. The cookie recipe resembled a basic chocolate whoopie pie in a lot of ways but it also included peppermint extract for flavoring. It was just enough to add mint flavor without becoming completely overwhelming. I loved the way the cookies emerged from the oven too - tall and fluffy, which I always think make the prettiest whoopie pies :)
The book suggested sandwiching a frozen mint chip cream (made simply by combining whipped heavy cream, sweetened condensed milk, peppermint oil and grated chocolate) between the cookies. Obviously what you see in my whoopie pies is not the mixture I just described. I did make it, and let me tell you, it was beyond delicious, but for some reason mine just never froze enough to hold its shape when sandwiched between the whoopie pies. Rest assured it didn't go to waste - I ate it like ice cream with a spoon :) My fall back plan was a light, fluffy mint buttercream to which I added just a tiny bit of green gel food coloring. It's a buttercream I've made before and I like that it's not super buttery and that it has a really great texture for piping, whether it's on cupcakes or between these cookies. If you want to add a fun finishing touch, you can roll the sides of the filled whoopie pies in mini chocolate chips too! Visually, I think I liked them better without the chips, but they were both delicious so you can't go wrong either way.
Mint Chocolate Chip Whoopie Pies
cookies from The Whoopie Pie Book, filling from Whoopie Pies
Chocolate Mint Cookies
1 1/4 cups (175 g) all-purpose flour
3/4 cup (100 g) unsweetened cocoa powder
1 1/2 teaspoons baking soda
1/2 teaspoon baking powder
1/2 teaspoon salt
9 tablespoons unsalted butter, at room temperature
1 cup (200 g) sugar
1 large egg
1 cup buttermilk
1 teaspoon peppermint extract
Mint Buttercream Filling
2 cups confectioners' sugar, sifted
4 tablespoons (1/2 stick) unsalted butter, at room temperature
3 tablespoons heavy cream
2 teaspoons vanilla extract
1/2 teaspoon peppermint extract
1/2 teaspoon salt
green gel food coloring (optional)
To make the cookies: In a medium bowl, sift the flour, cocoa powder, baking soda, baking powder and salt together (I rarely sift, but I think it's worth it when it comes to cocoa powder, which can be quite lumpy). In the bowl of a stand mixer fitted with the paddle attachment, cream the butter and sugar on medium speed until light and fluffy, about 3-4 minutes. Add the egg and beat until combined. Mix in the buttermilk and peppermint extract (my batter looked curdled at this point, it'll come together in the next step). With the mixer on low, gradually add the dry ingredients, beating just until combined. Transfer the mixer bowl to your refrigerator and chill the dough for 30 minutes.
Meanwhile, preheat oven to 350 F. Line two baking sheets with parchment paper.
Using a small cookie scoop (mine measures about 1 1/2 inches across - you'll need to adjust the baking time accordingly if yours is larger), portion the batter onto one of the prepared baking sheets, spacing the cookies about 2 inches apart. (If there are any rough edges or batter sticking up, I like to use a wet fingertip to smooth it down. It makes the cookies look neater once baked, but it's not necessary.) Bake (one sheet at a time) for about 10 minutes, or until the cookies spring back when gently pressed. Transfer the baking sheet to a wire rack and let the cookies cool for a few minutes then remove the cookies to the wire rack to cool completely. Repeat with all of the dough, alternating baking sheets.
To make the filling: In the bowl of a stand mixer fitted with the paddle attachment, beat the confectioners' sugar and butter (first on low and then increasing the speed to medium) until evenly distributed and crumbly, about 1-2 minutes. Add the cream, extracts, and salt and beat on high speed until light, fluffy and smooth, about 3 minutes. If you want green buttercream, beat in a little bit of food coloring at a time until you achieve your desired color.
Match the cookies in pairs by size. Transfer the filling to a piping bag and pipe a small amount onto the flat side of one cookie of each pair. Sandwich the cookies together, and press the filling to the edges.
Makes about 24 whoopie pies