Combine Chocolate and 1 1/2 Tablespoons cream in heavy saucepan; cook over low heat until the chocolate melts. Beat cream cheese in a small mixing bowl, add sugar, ! Tablespoon cream and the chocolate mixture ( I usually wait til it melts and cools a minute or so). Gradually add kahlua. Set aside.
Whip remaining cream in separate bowl until stiff with electric mixer on high spped; add powdered sugar. Fold the chocolate mixture from step1 into this blending until smooth. Spoon into crust. Freeze until firm ( I usually leave all day or overnight). Add coll whip before serving to each slice. Store in freezer - if there is any left!