01 -
Preheat oven to 350°F. Line baking sheets with parchment paper or silicone mats. In a medium bowl, whisk together flour, cocoa powder, cornstarch, baking soda, and salt.
02 -
In a separate bowl, beat softened butter, granulated sugar, and brown sugar until fluffy. Add egg, vanilla extract, vinegar, and red food coloring and mix until combined.
03 -
Gradually add dry ingredients to wet mixture, stirring until just combined without overmixing.
04 -
Use a cookie scoop to portion 1-tablespoon dough balls. Place 2 inches apart on prepared sheets. Bake 7–9 minutes until tops are set but not browned. Cool completely on sheets before transferring to wire rack.
05 -
Beat butter, shortening, and cream cheese until smooth. Gradually add powdered sugar and salt, beating until fluffy. Adjust consistency with heavy cream, 1 tablespoon at a time, if needed.
06 -
Spread or pipe frosting onto the bottom of one cookie, then sandwich with a second cookie. Repeat with remaining cookies and frosting.