Preheat your oven to 350°F (175°C).
In a bowl, whisk together flour, cocoa powder, baking soda, and salt.
In a separate bowl, cream the softened butter and sugar until light and fluffy.
Add the egg, food coloring, and vanilla extract to the butter mixture and mix well.
Gradually add the dry ingredients to the wet mixture, stirring until combined.
Chill the dough in the refrigerator for about 30 minutes.
Using a cookie scoop, drop dough onto a baking sheet lined with parchment paper.
Bake for 12-15 minutes, until the edges are set.
Remove from the oven and let cool on the baking sheet for a few minutes.
Transfer to a wire rack to cool completely.
Once cooled, spread cream cheese frosting on one cookie and sandwich with another.