Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, combine the all-purpose flour, cocoa powder, granulated sugar, brown sugar, baking powder, baking soda, and salt. Mix well to ensure there are no lumps.
Create a well in the center of the dry ingredients. Pour in the vegetable oil, eggs, and vanilla extract.
Using a whisk or wooden spoon, mix until all ingredients are well combined and form a thick batter. The dough will be sticky.
Chill the cookie dough in the refrigerator for about 30 minutes to firm it up slightly, which makes it easier to handle.
Once chilled, use a spoon or cookie scoop to portion out the dough (about 1 tablespoon each) and roll them into balls.
Roll each ball in powdered sugar, coating them generously. Place them on the prepared baking sheet about 2 inches apart.
Bake in the preheated oven for 10-12 minutes, or until the cookies are puffed and have set edges but are still soft in the center.
Remove from the oven and let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
Notes
Arrange the cookies on a beautiful platter and dust with extra powdered sugar before serving for a festive touch!