In a medium bowl, mix together the cocoa powder, white sugar, and vegetable oil.

Beat in the eggs one at a time, then stir in the vanilla extract.

In a separate bowl, combine the flour, baking powder, and salt. Stir the dry ingredients into the cocoa mixture until combined.

Preheat the oven to 350°F. Line cookie sheets with parchment paper or a silicone baking mat.

Roll the chilled dough into 1-inch balls. Roll each ball in confectioners' sugar until coated.

Place the dough balls on the prepared cookie sheets, leaving space between them.

Bake for 10 to 12 minutes.

Allow the cookies to cool on the cookie sheet for about 1 minute before transferring them to wire racks to finish cooling.