In a medium bowl, whisk together the cocoa powder, granulated sugar, and vegetable oil until combined.

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

In a separate bowl, whisk together the flour, baking powder, and salt.

Gradually stir the dry ingredients into the wet mixture until a soft dough forms.

Cover the dough and refrigerate for at least 4 hours or overnight to ensure the dough is firm enough to roll.

Preheat oven to 350 degrees F (175 degrees C) and line baking sheets with parchment paper.

Scoop rounded tablespoons of dough and roll into 1-inch balls.

Roll each ball generously in confectioners' sugar until heavily coated.

Place balls 2 inches apart on the prepared baking sheets.

Bake for 10 to 12 minutes until the edges are set but the centers remain soft to the touch.

Let cool on the baking sheet for 5 minutes before transferring to a wire rack.