In a bowl, cream together 1 cup of softened butter with the sugar until light and fluffy.
Beat in eggs until fully incorporated.
Add the flour, cocoa powder, and baking soda into the wet ingredients, and mix together until combined.
Turn the dough out onto your surface and push together into a flat square for ease of rolling out, divide the dough into 4 parts. You can wrap the dough your not using yet and keep it in the refrigerator until you ready.
Preheat oven to 325˚F.
Place the dough between the two sheets of parchment paper or a silicone mat with parchment paper on top of the dough roll out to ¼-inch in thickness.
Using a small round cookie cutter about the size of the rim of a champagne glass.
Place on a large parchment lined baking sheet, leaving at least ½-inch between each cookie.
Pack together and re-roll out any scraps to cut additional cookies. Repeat with this process with each remaining ¼ of the dough.
Bake in a preheated oven for 15 minutes.
Remove and transfer cookies to a cooling rack to cool completely.
To make the filling, combine butter, powdered sugar, and vanilla in a medium mixing bowl. Beat together until light and fluffy.
Assemble the cookies by spreading a generous scoop of the icing onto one of the cookies and sandwiching it with another. Give it a light squeeze and scrape any excess off to clear and even out the sides.
Stored in an airtight container for 3 days. Note they may become less crispy the longer they’re stored.
