How to Make It
Prepare the Chocolate Sugar Cookie Dough: Beat butter and sugar with a heavy-duty electric stand mixer on medium-high speed until light and fluffy, about 3 minutes. Add eggs and vanilla. Beat on medium until combined, stopping to scrape down sides of bowl as needed. 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 350°F. 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.
Prepare the Filling: While cookies cool, beat unsalted butter and cream cheese with a heavy-duty electric stand mixer on medium speed until creamy, 1 to 2 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.
Using a small food-safe paint brush, paint 3 lengthwise stripes of red food coloring gel on the inside of a piping bag fitted with a large star tip. Fill bag with frosting. Pipe frosting onto half of cookies, and sandwich with remaining cookies. Refrigerate 15 minutes before serving to firm up frosting.