Mix granulated sugar, oil, chocolate and vanilla. Mix in eggs, one at a time. Stir in flour, baking powder and salt. Cover and refrigerate for at least 3 hours. Heat oven to 350 degrees. Drop dough by teaspoonfuls into powdered sugar; roll around to coat. Shape into balls. Place about 2 inches apart on greased cookie sheet. Bake for 10-12 minutes.