Preheat oven to 350oF -- Coat 9 inch spring-form pan with cooking spray. Wrap outside, including bottom of pan, with heavy-duty foil.
Crust: in blender process cookies until finely ground. Transfer to bowl;combine with butter. Press into bottom and 1/2 inch up side of pan. Bake 10 minutes; set aside on rack.
Cake: At high speed beat cheese and sugar until smooth. Reduce speed to low; beat in egg substitute, sour cream and vanilla.Increase speed to medium high; beat 5 minutes. In bowl stir cocoa into water until smooth, stir in 1 1/2 cups batter until combined. Pour half of remaining plain batter into crust. By spoonfuls drop half of chocolate mixture onto batter in pan. Top with remaining plain batter and spoonfuls of chocolate mixture. Pull knife through batter to create swirls. Place pan in roasting pan; fill roasting pan with hot water halfway up side of spring-form pan.
Bake 1 hour or until center is set. Remove from water; remove foil. Run knife around edge of cake. Cool on rack 1 1/2 hours; refrigerate 8 hours or overnight. Remove side of pan; transfer to serving plate.
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