01 - Whisk together flour, cocoa powder, baking powder, and salt in a medium bowl.
02 - In a large bowl, blend sugar and vegetable oil. Incorporate eggs one at a time, then stir in vanilla extract.
03 - Gradually combine dry ingredients with wet mixture, stirring until a sticky dough forms.
04 - Cover dough and refrigerate for at least 1 hour until firm.
05 - Preheat oven to 350°F. Line baking sheets with parchment paper.
06 - Scoop heaping tablespoons of dough, roll into balls, then coat generously in powdered sugar.
07 - Arrange dough balls 2 inches apart on the prepared baking sheets.
08 - Bake for 10 minutes until cookies are set but remain soft in the center.
09 - Allow cookies to cool on baking sheets for 5 minutes before transferring to a wire rack to cool completely.