In a large mixing bowl, combine the instant vanilla pudding, powdered sugar, vanilla and milk using a handheld or standing mixer. Beat on medium high for about a minute and a half, you will end up with a very thick mixture.
Next, beat in one tub of Cool Whip until it's mostly incorporated. Repeat the same process with the second and third tubs of Cool Whip, adding one at a time until well combined.
Your frosting should become stiffer as you beat it and stand up into peaks on the whisk attachment.
Once all the Cool Whip has been incorporated and the mixture is smooth, your Cool Whip Frosting is ready to use.
You can apply the frosting right away or store it in the refrigerator until you're ready to use it. If you're not using it immediately, be sure to cover it to prevent it from drying out.
*Y*ou don’t technically NEED 3 tubs of cool whip to make this frosting BUT I added three and maintained the flavor without it tasting TOO much like pudding. You can technically make this recipe with only 1 or 2 tubs but it retains its consistency and shape with 3 (8oz) tubs just fine and I prefer the flavor balance.