1 cup unsalted butter, softened
1 cup white sugar
2 large eggs
2 cups all-purpose flour
1¼ cups dark chocolate/special dark cocoa powder
½ teaspoon baking soda
½ cup butter, softened
2 cups powdered sugar
1 teaspoon vanilla
1. In a large bowl, cream together 1 cup of softened butter with the white sugar, until light and fluffy.
2. Beat in eggs until fully incorporated.
3. In a separate bowl, whisk together the flour, cocoa powder, and baking soda, breaking up any large clumps.
4. Add the dry ingredients to the wet ingredients, and mix together until combined.
5. Turn the dough out onto your surface and push together into a flat square. Wrap the dough in plastic wrap and refrigerate for 1 hour.
6. Preheat oven to 325˚F/160˚C.
7. Remove the dough from the fridge, and for ease of rolling out, divide the dough into 4 (this way the dough stays cool longer and prevents the need of re-chilling later on).
8. To roll out the dough, place a quarter of the dough between two sheets of parchment paper (alternatively the dough can be rolled out on a lightly floured surface - though the parchment is prefered as it prevents any additional flour from altering the color/appearance of the dark cookies). Roll the dough between the two sheets of parchment to ¼-inch thickness.
9. Using a small round cookie cutter (alternatively, we found the rim of a champagne glass to be the perfect size!) cut the dough into individual rounds and place on a large parchment-lined baking sheet, leaving at least ½-inch between each cookie.
10. Pack together and re-roll out any scraps to cut additional cookies. Repeat with this process with each remaining ¼ of the dough.
11. Bake in a preheated oven for 15 minutes. If baking multiple trays at the same time, be sure to rotate the pans in the oven halfway through.
12. Remove and transfer cookies to a cooling rack to cool completely.
13. To make the filling, combine ½ cup butter, powdered sugar, and vanilla in a medium mixing bowl. Beat together until light and fluffy.
14. 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.