In a separate large bowl, whisk together the flour, baking powder and salt. Set aside.
In the bowl of an electric mixer fitted with the paddle attachment (or in a large bowl, using a hand mixer) beat together the cocoa powder, white sugar, and vegetable oil.
Add the eggs, one at a time, mixing well after each addition.
Add the vanilla and beat in thoroughly.
On low speed, mix reserved dry ingredients into cocoa, sugar, oil, eggs and vanilla mixture. Stir until just combined. Do not overbeat.
Cover the dough with plastic wrap and chill for four hours or overnight.
Preheat the oven to 350°F and line baking sheets with parchment paper.
Place the confectioner's sugar in a shallow bowl or glass pie plate.
Scoop out a rounded teaspoon of the chilled dough and using your hands roll them into an approximately 1-inch (2.5 cm) balls.
Roll the balls in the confectioner's sugar and place on the cookie sheets.
Bake at 350°F for 10-12 minutes. (Mine took 12 minutes)
Remove from oven and place pan on a wire rack and allow to cool for a minute or two on the sheets before transferring to a wire rack to cool completely.
Notes
TIPS
- In between scooping the dough on to the cookie sheet, keep the mixture chilled.
- I used a small 3.5 cm diameter scoop to help form the cookies, but a teaspoon would work too.
- You may be tempted to dampen the scoop, but don't. I have tried it before and it muddles the "crinkle factor"! The chocolate and white colours won't be as distinct.
- I use this SEQUENCE to make the cookies: Scoop enough for one pan - roll these into balls - wash and dry your hands and then roll dough balls in icing sugar - bake.