Mix the sugar, baking cocoa, butter, oil, and vanilla in a large bowl. Gradually add the eggs and stir until well blended. Add the flour, baking powder and salt. Stir until well combined into a thick dark batter.

Refrigerate for at least 3 hours, until the batter looks more like a dough.

Form the dough into balls just over 1 inch in diameter. Roll the balls in the powdered sugar, and place 2 inches apart on a greased or parchment lined cookie sheet.

Bake at 350 degrees for 10-12 minutes. Remove from cookie sheets immediately to cool.