Grind crackers in a food processor with sugar.
Slowly add butter and churn well.
Press into a 9” pie plate and bake at 350 F for 10-15 minutes.
Chill well.
Whip cream cheese, sugar, and vanilla in a bowl until smooth.
Heat chocolate and half and half in a double boiler until melted.
Cool slightly and add to cream cheese mixture.
Fold in 8 oz. whipped topping and spoon into chilled crust.
Top with 4 oz. whipped topping and chill well.