1. Heat oven to 350°F. Grease and flour 13x9x2-inch baking pan.
2. Beat shortening, sugar and molasses in large bowl until blended. Add eggs; beat well. Stir baking soda into boiling water to dissolve; add to shortening mixture alternately with flour and salt. Remove 2 cups batter to medium bowl; add cocoa, blending well. Add spices to remaining batter in large bowl. Alternately spoon batters into prepared pan; swirl gently through batter with narrow spatula or knife for marbled effect.
3. Bake 40 to 45 minutes or until wooden pick inserted in center comes out clean. Cut into squares. Serve warm or at room temperature with sweetened whipped cream, if desired. 10 to 12 servings.