In a medium bowl, combine granulated sugar, cocoa powder and oil and beat with a hand mixer on medium speed until mixed together.
Add eggs one at a time, beating until well combined after each addition. Stir in vanilla.
In a separate bowl, combine flour, baking powder and salt.
Add dry ingredients to the wet ingredients and stir until well combined. Chill for 1 hour.
Preheat the oven to 350 degrees F. Line a cookie sheet with parchment paper and set aside.
Place powdered sugar in a bowl. Scoop out and roll dough into 1-inch balls and roll in powdered sugar until well coated. Place on the prepared cookie sheet.
Bake for 9–11 minutes.
Let cookies sit on the cookie sheet for a few minutes, then remove to a rack to cool completely.
Video
Notes
Make Ahead: Baked cookies can be stored in an airtight container for 3–4 days. Store dough in an airtight container in the refrigerator for up to 1 week before scooping, rolling and baking.