PREHEAT oven to 375°. Line 2 baking sheets with parchment paper.
FOR COOKIES: In a large bowl, beat butter and sugars with a mixer at medium-high speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add egg, beating well.
IN a medium bowl, whisk together Swans Down Cake Flour, cocoa, and baking soda. With mixer on medium speed, gradually add flour mixture to butter mixture, beating until combined. Add food coloring, vinegar, and vanilla, beating until combined. Drop cookies by tablespoonfuls at least 2 inches apart on prepared pans. Refrigerate for 10 minutes.
BAKE until lightly golden, about 8 minutes. Let cool on pans for 5 minutes. Remove from pans, and let cool completely on wire racks.
FOR FROSTING: In a large bowl, beat cream cheese with a mixer at high speed for 1 minute. Reduce mixer speed to medium. Gradually add confectioners’ sugar, beating until smooth. Spread cream cheese frosting over cooled cookies. Reserve 2 cookies to crumble over frosting.
Makes 24 cookies