Chocolate-Peanut Butter Whoopie Pies

In a large bowl, using an electric mixer, beat the butter on high speed until fluffy and pale yellow. Add the sugar and beat until lightened. Add the eggs and vanilla and beat until well blended.

Sift the flour, cocoa, baking powder, baking soda and salt onto a sheet of parchment paper. Add to the butter mixture and beat on low speed just until blended. Cover and refrigerate the dough until firm, about 2 hours.

Preheat an oven to 350°F (180°C). Lightly butter 2 baking sheets.

With dampened hands, shape the dough into 3/4-inch (2-cm) balls and place them about 2 inches (5 cm) apart on the prepared baking sheets. Using a spatula, press down on each ball to flatten it slightly. Bake until the cookies are firm to the touch, 10 to 12 minutes. Transfer the cookies to wire racks and let cool completely.

Meanwhile, make the peanut butter filling: In a large bowl, beat the butter, confectioners’ sugar, peanut butter and vanilla until blended and smooth. Cover and refrigerate until the cookies are cool.

Spread the flat side of half of the cookies with 1 1/2 tsp. of the peanut butter filling. Top with a second cookie, flat side down, pressing lightly to make a cookie sandwich, and serve. Makes about 36 whoopie pies.

Adapted from Williams-Sonoma Dessert of the Day, by Kim Laidlaw (Weldon Owen, 2013).