Mix flour, cocoa powder, baking powder, and salt in a bowl. Set aside.

In a separate bowl, whisk sugar and vegetable oil until smooth. Add eggs one by one, followed by vanilla extract.

Gradually combine dry ingredients with wet ingredients, stirring until fully incorporated. The dough will be sticky.

Cover the bowl with plastic wrap and chill the dough for at least 1 hour.

Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper.

Roll the dough into 1-inch balls, then coat each ball generously in powdered sugar.

Place dough balls on the baking sheet, 2 inches apart. Bake for 10-12 minutes, or until the tops are cracked and the edges are set.

Cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.