1. Chop each peanut butter cup into 6 pieces; set aside. Microwave 50 chocolates in medium microwave-safe bowl on MEDIUM (50%) 1 minute or just until chocolate is melted when stirred; stir in 3-1/2 cups whipped topping until blended.
2. Spread half of chocolate mixture into crust; sprinkle with peanut butter cup pieces. Top with remaining chocolate mixture. Refrigerate 3 hours or until set.
3. Spread with remaining whipped topping just before serving. Garnish each serving with additional candies, if desired. Makes 8 servings.