Crush the Twix bars into small pieces. You can do this by placing them in a zip-top bag and crushing them with a rolling pin or mallet.
In a medium bowl, whisk together the instant vanilla pudding mix and milk until well combined and the pudding begins to thicken. Let it sit for a few minutes as per pudding package directions.
Gently fold the thawed whipped topping into the prepared pudding until just combined. Be careful not to overmix.
To assemble the trifles, layer the ingredients in individual serving glasses or a large trifle dish. Start with a layer of crushed Twix bars, followed by a layer of the pudding mixture, and then another layer of crushed Twix bars. Repeat the layers until the glasses are full, ending with a topping of crushed Twix.
Chill the trifles in the refrigerator for at least 30 minutes before serving to allow the flavors to meld and the dessert to set.
Notes
For an extra touch, you can garnish with additional whipped cream and a whole Twix bar on top. These trifles are best served chilled.