In mixing bowl combine granulated sugar, oil, melted chocolate, and vanilla. Beat in eggs. Stir together flour and baking powder. Stir into chocolate mixture. Cover and chill. Using 1 tbsp dough for each cookie, shape into balls; roll in powdered sugar. Place on greased cookie sheet. Bake at 375 degrees F for 10-12 minutes. Roll warm cookies again in powdered sugar. Makes 4 dozen cookies.