Preheat oven to 375 degrees F.
Mix together flour, cocoa powder, baking powder, baking soda and salt in a small bowl.
Cream together the butter and sugar until light and fluffy, about 3 minutes. Add the eggs 1 at a time. Then beat in the buttermilk, vinegar, vanilla and red food coloring. Once combined, add the dry ingredients to wet. Mix until thoroughly combined.
Onto a parchment lined sheet tray, drop batter using an ice cream scoop, forming 2-inch round circles.
Bake for 10 minutes, until baked through. Cookies should be cake-like and light. Allow to cool for a few minutes on the baking sheet, then remove to a wire rack to cool completely.
In a large mixing bowl, beat the cream cheese, butter, and vanilla together until smooth. Add the sugar and on low speed, beat until incorporated. Increase the speed to high and mix until very light and fluffy.
Spread the cream cheese frosting between 2 cooled cookies and roll the edges in finely chopped pecans, if desired.