Crush 36 Oreo cookies into bite-sized chunks using a zip-top bag and a rolling pin, or pulse them in a food processor for a finer texture. Reserve a few whole cookies for garnishing.

In a large mixing bowl, combine 8 ounces of softened cream cheese and 4 tablespoons of softened unsalted butter. Use an electric mixer to beat until smooth. Gradually add 1 cup of powdered sugar, mixing until fully incorporated, then gently fold in 8 ounces of thawed whipped topping.

Select a clear serving dish and spread half of the crushed Oreo cookies across the bottom. Add half of the cream cheese filling on top.

Sprinkle a handful of pastel candy-coated chocolates over the first layer, then repeat with the remaining Oreo cookies and cream mixture, smoothing gently.

Cover the casserole with plastic wrap or a lid and refrigerate for at least 1 hour.

Before serving, add reserved whole Oreos and extra pastel candies on top. Serve chilled.