Preheat the oven to 190 degrees C. Line a cookie tray with parchment paper

In a large bowl, sift the flour, cocoa powder, baking powder, baking soda and salt

Using a stand mixer or hand mixer, cream the butter and sugars until light and fluffy, about 4 to 5 mts

Beat in the egg and the vanilla extract

In a small cup, mix together the buttermilk and the red food coloring

With the mixer on low speed, add the flour mixture (from step 2) and buttermilk mixture (from step 5) alternatively in 3 additions, starting and ending with flour. Mix till no streaks of flour remain

Using an ice cream scoop preferably, drop scoops of the batter onto the prepared cookie tray spacing them about 1.5inches apart. With the back of a spoon smooth the top of the batter

Bake for 9 to 10 mts. Remove from oven and cool completely on a cooling rack

To make the creamy filling, heat the milk on low flame till small bubbles start appearing along the side. Whisk the flour into the milk stirring continuously till it becomes very thick.

Remove the mixture from the heat and allow to cool completely to room temperature. Once the mixture is cooled completely, stir in the vanilla

Cream the butter and sugar till light and fluffy. Add the mixture from step 10 and beat until it resembles whipped cream

Pipe the creamy filling onto a cooled cookie and sandwich with another cookie