Whisk the flour, baking powder, salt, and cocoa powder together in a medium bowl.
Beat the eggs and sugar in a large bowl until combined.
Add the vegetable oil and mix until well incorporated.
Gradually add in the dry ingredients and mix until well combined.
Cover the batter with plastic wrap and place in the refrigerator for about an hour.
Preheat oven to 350 degrees.
Line two cookie sheets with parchment paper.
Pour the powdered sugar into a small bowl, deep bowl.
Scoop out some dough and form it into a ball using a small ice cream scoop. The dough will be sticky, so do this quickly. You may be tempted to wet your hands. Don't! The key is to get the dough into the powdered sugar quickly.
Drop the cookie dough ball in the powdered sugar, completely coating it. You should not see any cookie dough.
This should give you 36 cookies.
Bake in the oven until the cookies puff up a bit and are firm around the edges, about 7-8 minutes. Oven times vary so check them at 7.
Remove the cookies from the oven and allow them to cool for 5 minutes, then move to a wire rack to cool completely.