Combine raisins and water in a saucepan; bring to a boil. Remove from heat. Stir in salad oil, cool to lukewarm. Stir in sugar and egg. Sift together dry ingredients; beat into raisin mixture. Stir in nuts. Pour batter into greased 9 x 13" pan. Bake at 350* for 20 minutes or until done. When cooled cut into bars. Dust with powdered sugar.