Ingredients
Method
Make the Cookies
- Prepare your mint syrup at least 8 hours ahead to allow the mint leaves to fully infuse
- Preheat your oven to 350°F (175°C). Line cookie sheets with parchment paper, foil shiny side down, or lightly grease them
- In a medium bowl, whisk together the all-purpose flour, cake flour, cocoa powder, salt, baking powder, and baking soda. Set aside
- In a large mixing bowl, beat the butter and sugar together with an electric mixer until light and fluffy
- Beat in the eggs and vanilla extract until well combined
- Using a rubber spatula, stir in half the dry ingredients — avoid an electric mixer here or the dry ingredients will go everywhere. Mix in the milk, then stir in the remaining dry ingredients. The dough should be thick and hold its shape
- Refrigerate the dough for about 1 hour for easier shaping and more uniform cookies
- Drop dough by rounded tablespoons onto prepared cookie sheets, spacing 2 inches apart. Gently flatten each one slightly — even rounds are easier to sandwich. Makes approximately 50 cookies
- Bake for 10 minutes. Rest on the sheet for 5 minutes, then transfer to a wire rack. Cool completely before filling or they will melt the cream
Make the Filling
- Place the fresh mint leaves in a medium saucepan and gently crush with the back of a spoon. Pour in 1 cup of heavy cream and stir
- Heat over medium until the cream just begins to boil. Remove from heat, cover, and steep for 15 minutes
- Strain out the mint leaves and return the cream to the saucepan. Add the marshmallows and heat over medium, stirring, until they are completely dissolved. Pour into a heatproof bowl
- Whisk in the mint syrup and a few drops of green food coloring. Allow to cool completely to room temperature
- Whip the remaining 1 cup of cold heavy cream to soft peaks. Pour in the cooled mint marshmallow cream and continue whipping to piping consistency. For a stiffer filling, add a few tablespoons of confectioner's sugar at this stage
- Transfer filling to a piping bag or zip-lock bag and place in the freezer for 20 minutes. Do not over-freeze
Assemble
- Snip a small corner off the piping bag. Lay cookies flat-side up on wax paper
- Pipe filling generously onto half the cookies, then press the remaining cookies on top to form sandwiches
- Individually wrap each whoopie pie and store in the refrigerator
Notes
Make the mint syrup at least 8 hours before baking — overnight is easiest. Chilling the dough before scooping and using a cookie scoop gives you more uniform, evenly-matched cookies. For a stiffer filling that holds its shape better, whisk in 2–3 tablespoons of confectioner's sugar before piping. Store individually wrapped in the fridge for up to 3 days
