Melt chocolate in a small bowl over hot, not boiling water or in a microwave oven at medium (50 percent) power. Set aside. In a medium-sized bowl, stir together flour, cocoa and salt. In a large bowl, whisk together egg whites and eggs. Add sugar, corn syrup, applesauce, oil and vanilla. Whisk in the chocolate. Add the flour mixture to the egg mixture and stir with a wooden spoon until blended. Pour into the prepared pan and sprinkle with walnuts. Bake for 30 to 35 minutes, or until a cake tester inserted in the center comes out clean. Let cool in the pan on a rack. Cut into squares. Serves 24. Calories: 129 per serving; Protein: 2 grams; Fat: 4 grams; Carbohydrate: 23 grams; Sodium: 64 milligrams; Cholesterol: 18 milligrams.