Adjust oven rack to middle position and heat oven to 325° degrees. Line 2 baking sheets with parchment paper.

In a medium-sized bowl, mix together the cocoa powder, white sugar and vegetable oil. Beat in eggs one at a time, until fully incorporated. Mix in the vanilla.

In another bowl, combine the flour, baking powder, and salt.

Stir the dry ingredients into the wet mixture just until a dough forms (do not over beat). 

Cover the the bowl with plastic wrap and chill the dough in the refrigerator for 2 hours.

 Measure the granulated and confectioners’ sugar into separate shallow dishes. Working with 2 tablespoons dough (or use #30 scoop) at a time, drop dough balls directly into granulated sugar and roll to coat. Then transfer dough balls to confectioners’ sugar and roll to coat evenly.

Evenly space dough balls on prepared sheets, 11 per sheet.

Bake cookies, 1 sheet at a time, until puffed and cracked and edges have begun to set but centers are still soft. The cookies will still look a little moist or raw between cracks. Bake for about 12 minutes, rotating the cookie sheet halfway through baking.

Let the cookies cool for 8 minutes on the cookie sheet before transferring to a wire cooling rack to cool completely.