Preheat oven to 375°F. Mix all ingredients together in one bowl and combine well.
Place the bowl with the batter in the fridge for 20 minutes.
Remove bowl from the fridge and dust your surface generously with cocoa powder, the dough will be very sticky.
Form your dough into a ball with your hands and roll it to the desired thickness.
Use the cookie cutter to cut out the sandwich shapes and place them on a cookie sheet with a silicone mat on top.
Bake cookies for 8-10 minutes.
Allow them to rest for 5 minutes before moving them to a cooling rack. They will be softer and can break when fresh out of the oven.
Fill the cookies with the filling from the freezer and enjoy (or keep in the freezer in an airtight container) for up a few weeks - if they last that long.