Crush the Golden Oreos to fine crumbs using a food processor, or place cookies in a resealable bag and crush with a rolling pin.
Combine the crushed Oreos with the melted butter until evenly moistened, then press the mixture firmly into the bottom of a 9×13-inch pan to form the crust.
In a medium bowl, beat the softened cream cheese with the 1/2 cup margarine or butter and the powdered sugar until smooth.
Fold in half of the Cool Whip (about 1 cup) into the cream cheese mixture until combined, then spread this layer over the Oreo crust.
In a separate bowl, whisk the instant pudding mix with the milk until the pudding thickens, then pour it over the cream cheese layer and spread evenly.
Top the pudding layer with the remaining Cool Whip, spreading to cover the surface.
Use a vegetable peeler or grater to shave the white chocolate bar into curls and sprinkle them over the top.
Refrigerate the assembled lasagna for at least 1 hour before slicing and serving.
