In small microwave-safe bowl, place chocolate. Microwave at HIGH (100%) 1 to 1-1/2 minutes or until chocolate is melted and smooth when stirred.
In small bowl, beat butter, sugar, cream cheese and milk until well blended and smooth; blend in chocolate.
Fold in 2 cups whipped topping; spoon into crust. Cover; refrigerate until firm, about 3 hours. Garnish with additional whipped topping, if desired. 6 to 8 servings.
Developed and Tested by the Hershey Kitchens