Instructions

1. preheat oven to 350 degrees.
2. in a large bowl, add the flour, cocoa powder, baking soda and salt. whisk together until well combined and set aside.
3. in a small bowl, stir together the buttermilk and vanilla and set aside.
4. in the bowl of an electric mixer, fitted with the paddle attachment, beat together the butter and the brown sugar until creamy and fluffy. about 3 mins. add the egg and beat until well combined. add the flour mixture and buttermilk in batches, starting and ending with the flour. scrape down the bowl several times, ensuring that everything is well combined. mix just until all the ingredients are combined, do not over mix.
5. using a pastry bag fitted with a large circle tip, pipe out the batter in 1 1/2 inch circles on a baking sheet lined with parchment paper, leaving at least 1 inch between each.
6. dip your finger in water and shake off excess. with your wet finger, gentley press down the top of each cookie.
7. bake in 350 degree oven for 8-10 mins., until they are puffed. using a metal spatula, transfer to a wire rack and cool completely.

vanilla buttercream:

1. in the bowl of an electric mixer fitted with the paddle attachment, beat together the butter and sugar. start on low speed until combined and then increase speed to medium and beat for approx. 3 mins. add vanilla and cream and beat again. about 1 min more.

assembly:

1. match up cookies in like sized pairs. pipe out or spoon buttercream on one side and sandwich with the other.