Begin by crushing 24 Oreo cookies into fine crumbs using a food processor or by placing them in a zip-top bag and rolling over with a rolling pin. Mix the crumbs with ½ cup of melted unsalted butter until well combined. Press this mixture firmly into the bottom of a 9x13-inch pan to create an even layer. Chill in the refrigerator for at least 15 minutes to allow the crust to set.

In a mixing bowl, beat 8 ounces of cream cheese with 1 cup of granulated sugar, ½ cup of milk, and 1 teaspoon of vanilla extract until smooth and creamy, about 2-3 minutes. Gently fold in 8 ounces of whipped topping until just incorporated. Spread this luscious cream cheese mixture evenly over the chilled Oreo crust.

In separate bowls, combine 1 package of chocolate pudding mix and 1 package of vanilla pudding mix with 1½ cups of cold milk each. Whisk the chocolate pudding for about 2 minutes until it begins to thicken, then pour over the cream cheese layer. Next, do the same with the vanilla pudding.

Top the layered puddings with the remaining whipped topping, spreading it smoothly. Sprinkle mini M&Ms or holiday candies on top along with Christmas sprinkles. Cover the dessert and chill in the refrigerator for at least 4 hours, preferably overnight.

Once chilled, use a hot knife to cut through the layers neatly and serve cold.