Chocolate Covered Strawberry Whoopie Pies

For the chocolate cookie-cakes:

• 1 ¾ cups all-purpose flour

• ¾ cup unsalted butter, room temperature

• 1 cup granulated sugar

• ⅔ cup cocoa powder

• ½ teaspoon salt

• 1 teaspoon baking powder

• ¼ teaspoon baking soda

• 1 teaspoon instant espresso powder

• 1 egg large, room temperature

• ½ cup buttermilk

• 1 teaspoon vanilla extract

• ¼ cup hot water

For the strawberry marshmallow creme filling:

• 34 grams freeze dried strawberries

• ⅓ cup water

• ¾ cup granulated sugar

• ¾ cup light corn syrup

• 1 teaspoon vanilla extract

• 4 ounces fresh egg whites (about 3-4 large eggs)

• ½ teaspoon cream of tartar

• Pinch salt

Adapted from Preppy Kitchen and Kickass Baker

1. Make the cookie-cakes: Preheat oven to 375℉. 

2. In a large mixing bowl sift together flour, cocoa powder, baking soda, baking powder, and salt. Stir in espresso powder. Set aside.

3. In a separate medium bowl, whisk together the egg, buttermilk, and vanilla.

4. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter on medium speed and slowly add sugar until light and fluffy. 

5. Reduce mixer speed to low. Starting with the dry mixture, alternate adding the dry and wet mixtures to the butter in the stand mixer. Use a silicone spatula to periodically scrape down the sides of the bowl. Slowly add the hot water.

6. Line baking trays with parchment paper. Scoop batter out using a small cookie scoop or one heaping tablespoon at a time, and drop onto prepared baking sheets, spacing 2-inches apart.

7. Lightly wet hands and carefully flatten any rough spots to create smooth, rounded tops to the batter.

8. Bake for 8-10 minutes until cookie-cakes spring back when touched or a cake tester inserted into the center comes out clean.

9. Let cool on the baking tray for about 5 minutes then use a spatula to transfer to a wire rack to cool completely. 

10. Make the marshmallow creme: Place the freeze-dried strawberries into a food processor and grind to a fine powder. Set aside.

11. Add the water, sugar, vanilla, and corn syrup in a small saucepan, stirring to combine. Warm over medium-high heat until the mixture reaches 240°F on a thermometer. Do not allow it to pass 240ºF.

12. While the sugar is heating, place the egg whites in the bowl of a stand mixer fitted with the whisk attachment. Whisk on medium speed until the egg whites are foamy. Increase the speed to high and add in the cream of tartar and salt. Continue to mix until soft peaks form. Add in finely ground strawberries and continue whisking until well combined, stopping to scrape the sides of the bowl as needed.

13. Once the sugar mixture reaches 240°F, carefully remove it from the heat and let rest for about 20 seconds. Reduce mixer speed to medium and very carefully and slowly stream the sugar mixture into the egg whites. Once all the sugar has been added, increase the mixer speed to high and continue to mix until the outside of the mixing bowl returns to room temperature.

14. Transfer filling to a piping bag fitted with a large round tip and pipe a large dollop of marshmallow fluff over half of the cookie-cakes. Sandwich a second cookie-cake over the top.

15. Store whoopie pies in an airtight container set on parchment paper, in a single layer, in the refrigerator for up to 3 days. Let rest at room temperature about 30 minutes before serving. Extra marshmallow fluff can be stored in an airtight container in the refrigerator. Allow to come to room temperature before using.