Chocolate Marshmallow Sandwich Cookies (Whoopie Pies)
Soft chocolate sponge cake rounds sandwiched with a rich, creamy filling — a classic American treat reminiscent of homemade devil's food cake.
Ingredients
Chocolate cookies - low-gluten flour
2 cup
Chocolate cookies - non-alkalized cocoa powder (untreated)
1 cup
Chocolate cookies - salt
3/8 tsp
Chocolate cookies - unsalted butter (softened)
1/2 cup (1)
Chocolate cookies - granulated sugar
1 cup
Chocolate cookies - egg yolk
1 large egg
Chocolate cookies - vanilla extract
1 tsp
Chocolate cookies - baking powder
1 tsp
Chocolate cookies - hot water
1/2 cup
Chocolate cookies - buttermilk
1/2 cup
Buttercream filling - powdered sugar
2 cup
Buttercream filling - unsalted butter (softened)
4 tbsp (half)
Buttercream filling - heavy cream
3 tbsp
Buttercream filling - vanilla extract
1 tsp
Buttercream filling - salt
a pinch
Instructions
1
Make the cookies
Place a rack in the center of the oven and preheat to 400°F (about 205°C); butter two baking sheets. In a medium bowl, whisk together the flour, cocoa powder, and salt until well combined; set aside. Using a stand mixer fitted with the paddle attachment, beat the butter and sugar on medium-high speed until well combined, about 2 minutes. Add the egg yolk and beat until well combined, scraping down the sides of the bowl as needed. Add the vanilla extract and mix to combine. Stir the baking powder into the hot water until dissolved. Add the hot water mixture, the buttermilk, and the dry ingredients alternately in three additions, beginning and ending with the dry ingredients; beat until just combined. Using wet hands, shape the dough into 1-inch balls and place them 2 inches apart on the baking sheets. Wet your palms and press each ball into a 1 1/4-inch disk. Bake one sheet at a time for 5 to 7 minutes, until the surfaces are cracked (the centers will still be very soft and will firm up as they cool). Immediately transfer to a wire rack to cool completely.
2
Make the buttercream filling
Using a stand mixer fitted with the paddle attachment, beat the powdered sugar and butter on medium speed until light and fluffy, about 1 minute. Add the heavy cream and beat on high speed until smooth. Add the vanilla extract and salt and beat until well combined.
3
Assemble the cookies
Using a small metal offset spatula, spread 1 full teaspoon of buttercream filling over the bottom of half the cookies. Top with the remaining cookies and press gently to adhere.
4
Storage
Store in an airtight container at room temperature for up to 5 days.
