Sift cocoa, flour, salt and baking soda and mix well. Add vanilla, sweetener, eggs. Stir until well-blended and add the dry ingredients. Mix until well-blended, stir in chopped nuts, pour into a greased 20 cm square pan. Level batter smoothly. Bake at 160ºC or 20 minutes. Cut into 16 squares. Calories: 82 Exchanges: half bread, -20ºC at