In a medium mixing bowl, whisk together the 3.4-ounce box of instant vanilla pudding mix and 1 cup cold milk until smooth and well combined.
Gently stir in 4 ounces of Cool Whip until fully incorporated.
Refrigerate the pudding mixture for 10–15 minutes, or until slightly thickened.
Divide the vanilla wafers into two equal groups. Spoon about 2 teaspoons of the pudding mixture onto the flat side of each wafer in the first group.
Place the chocolate chips in a shallow microwave-safe bowl. Microwave in 30-second intervals, stirring well after each interval, until the chocolate is completely melted and smooth. Be careful not to overheat the chocolate.
Dip the tops of the remaining vanilla wafers into the melted chocolate, allowing any excess chocolate to drip back into the bowl.
Place each chocolate-dipped wafer on top of a pudding-covered wafer to form a sandwich.
Arrange the cookies on a tray and refrigerate until the chocolate is completely set.
Serve chilled and enjoy.
Notes
These cookies are best served fresh, but you can refrigerate the leftovers in an airtight container for up to 2-3 days.