Preheat your oven to 350°F. Line 2 large baking sheets with parchment paper and set aside.
In a medium sized bowl, whisk together flour, cocoa, milk powder, cornstarch, baking powder, baking soda, and salt to combine. Set aside.
In a large bowl, combine butter, oil, and brown and granulated sugars. Whisk together until smooth.
Whisk in the egg and vanilla to combine. Add in vinegar and as much food coloring as you need to reach your desired color and mix to combine.
Add the dry ingredients and fold together until you get a thick cookie dough. The dough will be sticky.
Use a large (3 to 4 tablespoon) sized cookie scoop to scoop dough onto parchment lined baking sheets, leaving about 3 inches of space between each cookie.
Bake the cookies in the center of your preheated 350°F oven for 12 to 15 minutes or until puffed and spread out with light golden bottom edges.
Cool the cookies for about 5 minutes on the baking sheet, then transfer to a wire rack to cool completely before frosting.
Make the frosting: In a medium bowl, cream together cream cheese and butter until smooth and lump free.
Add vanilla and powdered sugar and mix until smooth. Chill if frosting is too soft.
Pipe or spread frosting onto cooled cookies. Crumble any wonky cookie pieces and sprinkle on top as decoration.