Combine all-purpose flour, cocoa powder, baking powder, and salt in a bowl. Mix together using a wire whisk. Set aside.
Pour oil and add the granulated white sugar in a clean bowl.Beat using a hand blender (or stand mixer). Add the eggs and vanilla extract while beating.
Gradually add the flour mixture while beating and continue to beat until all the ingredients are well incorporated.
Cover the bowl with a cling wrap. Refrigerate for 8 hours or overnight.
Preheat oven to 350F. Scoop 1 tablespoon of mixture and roll it into a ball. Roll the ball in a plate with powdered sugar.
Put a parchment paper over a baking tray or cookie sheet. Arrange the coated balls o the baking tray with enough space apart.
Bake for 10 to 11 minutes.
Remove from the oven and let it cool down by placing in a wire rack.