In a medium bowl, mix together cocoa, white sugar, and vegetable oil. Beat in eggs one at a time, then stir in the vanilla.
Combine the flour, baking powder, and salt. Stir into the cocoa mixture.
Cover dough and chill for at least 4 hours.
Preheat oven to 350.
Line cookie sheets with parchment paper.
Roll dough into one inch balls. I like to use a number 50 size scoop.
Coat each ball in confectioners sugar before placing onto prepared cookie sheets.
Bake in preheated oven for 10-12 minutes. Let stand on the cookie sheet for a minute before transferring to wire racks to cool.