Preheat the oven to 375 F and line a baking sheet with non-stick foil.

In a food processor, blend flour, cocoa powder, baking soda, baking powder, salt, and sugars.

Add a few cubes of butter at the time to the food processor and pulse. Continue until all the butter is added.

Add the egg and mix until the mixture forms a dough.

Scoop small balls of dough onto the lined baking sheet and flatten.

Bake for 10 minutes, then cool on the baking sheet for a couple minutes before transferring to a wire rack to cool completely.

Beat all ingredients until fluffy.

Pair up similar sized cookies and spread filling on the bottom of one cookie from each pair. Press the bottom of the other cookie onto the cream to form a sandwich.