Crush 36 Oreo cookies into fine crumbs in a food processor, or place them in a sealed plastic bag and roll over the bag with a rolling pin. Reserve about 1/2 cup of the crumbs for the topping, then press approximately half of the remaining crumbs into the bottom of a 9 x 13-inch baking dish or large trifle bowl.

Beat the softened butter, softened cream cheese, powdered sugar, and vanilla extract until smooth and creamy. In a separate bowl, whisk the two pudding mixes with the cold milk for about 2 minutes, or until thickened.

Fold the thickened pudding into the cream-cheese mixture until evenly combined. Gently fold in the thawed whipped topping so the filling stays light and fluffy.

Spread half of the filling over the first Oreo layer, smoothing it into an even layer with a spatula. Add another layer of Oreo crumbs, followed by the remaining filling.

Finish the dessert with the reserved Oreo crumbs, then decorate with Christmas sprinkles, red and green candies, crushed peppermint, or other holiday decorations. Cover the dish and refrigerate for at least 4 hours; chilling overnight is best.