In a food processor or blender, grind the plain chocolate wafers into fine crumbs. Generously coat a 22 cm or 23 cm springform pan with nonstick cooking spray. Pour the crumbs into the pan and tilt to coat the bottom and the sides evenly. Set aside.
Preheat oven to 180ºC . With an electric mixer, beat the fat-free cream cheese until soft. Add the sugar, cocoa, vanilla extract and raspberry preserves and continue beating until the ingredients are incorporated. Add the egg substitutes, fat free sour cream and salt and continue beating until no lumps remain and mixture is smooth and liquid. You may have to beat the mixture for several minutes to reach this consistency.
Pour the batter into the prepared pan. Place in oven and immediately reduce oven temperature to 300 degrees. Bake for one hour, or until center is set and firm to the touch. Turn off oven and allow cheesecake to stay in cooling oven for one hour longer. Remove and cool completely. Refrigerate overnight before serving.
To make the raspberry sauce, puree the raspberries in a food processor or blender. Strain the pulp through a tea strainer, Pressing to remove all the seeds. Discard seeds. Place the cornstarch in a saucepan and stir in the raspberry juice. Bring to a boil, stirring constantly until thickened. Remove from heat immediately to prevent lumps from forming. Cool and chill. Serve one tablespoon of sauce on top of each slice of cheesecake.
Cake can also be frozen for two to three weeks before serving. To serve, thaw for 2 days in the refrigerator, then allow to come to room temperature before slicing.
Makes 10 servings
Per serving, including raspberry sauce: Calories 254, Fat 3.7 grams, Cholesterol 11.3 milligrams, Sodium 405 milligrams