Add baking soda to boiling water mix and let cool. Cream shortening and sugar. Add eggs and water to creamed mixture and beat well. Sift flour, cocoa and salt. Fold flour mix and peanut butter chips into sugar and shortening. Add vanilla. Pour into buttered 13x9 pan. Sprinkle the cake batter with the blended topping mix and bake at 350* F for 45-50 min. Serves 12-16.