Ensure the whipped topping is fully thawed, ideally overnight in the refrigerator. Line an 8x8 inch baking pan with parchment paper, creating a 'sling' that overhangs the sides for easy removal.

Sift the 4 cups of confectioners' sugar. While optional, sifting is highly recommended to eliminate lumps and ensure the smoothest texture in the finished candy.

In a large mixing bowl, gently combine the thawed whipped topping, vanilla extract, and the pinch of salt. Mix slowly with a spatula until just incorporated. Do not overmix.

Begin adding the confectioners' sugar, one cup at a time, to the wet mixture. Use a sturdy wooden spoon or spatula to incorporate. Continue adding sugar until the mixture becomes extremely thick, difficult to stir, and resembles stiff cookie dough or clay. You must use enough sugar (up to 4 cups) to achieve this firm consistency.

Transfer the thickened candy mixture into the prepared 8x8 inch pan. Use a slightly dampened spatula or the back of a spoon to press the mixture firmly and evenly into the pan. Cover tightly and chill in the refrigerator for a minimum of 4 hours, or ideally overnight (10 to 12 hours) until completely firm.

Once firm, use the parchment paper sling to lift the candy block onto a cutting board. Cut the block into small, bite-sized pieces (approx. 1-inch squares). Alternatively, roll the portions into smooth balls, dusting your hands lightly with powdered sugar if needed.

Pour extra confectioners' sugar or the optional coatings onto a shallow dish. Gently toss each cut or rolled candy piece until fully coated on all sides. Tap off any excess sugar before placing on a wax paper-lined plate.

Store Cool Whip Candy in an airtight container in the refrigerator for up to 10 days, or freeze for up to 2 months. Always serve chilled.