Sift together the cocoa powder, flour, baking powder, salt in a large bowl, and set aside
STEP 2
In a large mixing bowl, cream the butter, sugar and brown sugar. Add the egg & yolk one at a time, then the vanilla, followed by the instant coffee.
STEP 3
Add the dry ingredients and mix until incorporated
STEP 4
Wrap with plastic wrap and cool in the refrigerator at least 1 hour.
STEP 5
Knead the dough slightly to help soften and avoid cracks when rolling. Place between 2 lightly floured sheets of parchment paper and roll into a 1/4-inch-thick rectangle.
STEP 6
Using a round cookie cutter, cut the dough into circles. Any scraps will have to be re-chilled before you can re-roll it
STEP 7
Place the cookies about 2 inches apart on ungreased baking sheets and chill for 20 minutes. Preheat the oven to 325f/165c.
STEP 8
Bake the cookies until they are set (about 20 minutes) be sure not to let them get too dark or the cookie will become bitter.