Crush the Oreos into coarse crumbs using a food processor or a zip-top bag and rolling pin.

In a large bowl, beat softened cream cheese and butter until pale and silky.

Gradually add powdered sugar and beat until the mixture becomes fluffy.

In a separate bowl, whisk milk and instant pudding mix until thick.

Fold the pudding mixture into the cream cheese mixture, then gently fold in the whipped topping.

Spread a layer of crushed Oreos in a casserole dish, then spoon a thick layer of creamy filling over the crumbs.

Sprinkle pastel candy-coated chocolates over the filling and repeat the layers until the dish is full.

Finish with a smoothing of filling on top, arrange whole Oreos around the edges, and sprinkle with remaining candies and rainbow sprinkles.

Refrigerate for at least 2 hours before serving to allow the pudding to set.