Line two large baking sheets with parchment paper or silicone baking mats, set it aside and preheat the oven to 350°F (177°C)
Mix the flour, cocoa powder, baking soda, and salt together.
In a large bowl using a mixer, beat the butter for 1 minute on medium speed until completely smooth and creamy. Add the brown sugar and beat on medium speed until fluffy and combined. Beat in egg on high speed, Once the egg is fully combined, beat in the vanilla and buttermilk. that's ok.
On low speed, slowly mix the dry ingredients into the wet ingredients until combined. Add enough food coloring to achieve a deep red hue (usually about 1 teaspoon gel). Spoon mounds of batter, about 1 and 1/2 Tablespoons each, onto prepared baking sheets-- about 3 inches apart.
Bake for 10-12 minutes or until centers appear set. Allow to cool completely before sandwiching.
In a large bowl using a mixer, beat the cream cheese for 1 minute until completely smooth and creamy. Then add the butter until combined.
Add the icing sugar and vanilla and beat on medium speed until combined and creamy.
Pair them up based on their size. Spread cream cheese filling onto the flat side of one cookie and sandwich with the other. Sprinkle confectioners' sugar on top of each if desired.