Soft, chocolaty cookies with a bright and refreshing peppermint cream filling.
Add eggs and vanilla.
Beat on medium until combined, stopping to scrape down sides of bowl as needed.

Credit:Caitlin Bensel; Food Styling: Torie Cox
Melt chocolate chips according to package directions, and cool.
Add to butter-sugar mixture; beat on low until blended.
Stir together flour, cocoa, baking powder, and salt in a medium bowl.
With mixer running on low speed, add flour mixture to butter mixture, beating until just incorporated.
Cover dough; chill 1 hour.
Prepare the Cookies:Preheat oven to 350F.
Shape dough into 48 (1-inch) balls.
Place sparkling sugar in a shallow bowl.
Roll each ball in sparkling sugar; place 2 inches apart onto 2 parchment paper-lined baking sheets.
Gently flatten dough balls to 1/2-inch thickness.
Bake in preheated oven until cookies are dry to the touch, about 8 minutes.
Cool on baking sheets 2 minutes.
Transfer cookies to a wire rack to cool completely, about 30 minutes.
Reduce speed to low, and, with mixer running, gradually add powdered sugar, beating until smooth.
Beat in heavy cream, vanilla extract, and peppermint extract.
Fill bag with frosting.
Pipe frosting onto half of cookies, and sandwich with remaining cookies.
Refrigerate 15 minutes before serving to firm up frosting.