In a mixing bowl, beat granulated sugar, vegetable oil and the cocoa powder on high for 2 minutes. Add eggs and vanilla, beat 2 minutes until smooth. In another bowl, combine flour, baking powder and salt. With mixer at low, add to the cocoa mixture. Chill 6 hours or overnight.

When ready to bake, preheat oven to 350°F. Grease 2 large baking sheets. Place confectioners’ sugar in small shallow bowl. Shape dough into 1″ balls and roll in confectioners’ sugar. Bake 12 to 14 minutes. Cool on baking sheet 1 minute, then remove to wire racks. Garnish with chocolate curls.