Place the Golden Oreos in a food processor and pulse until finely crushed; alternatively put cookies in a resealable bag and crush with a rolling pin.
Mix the melted butter into the crushed Oreos until fully combined, then press the mixture firmly into the bottom of a 9x13-inch pan to form an even crust.
In a medium bowl, beat the softened cream cheese with the margarine or butter and powdered sugar until smooth.
Fold half of the Cool Whip (about 8 oz) into the cream cheese mixture until evenly incorporated, then spread this layer over the Oreo crust.
In a separate bowl, whisk the instant pudding mix into the milk until the pudding thickens, about 1–2 minutes, then pour the pudding over the cream cheese layer and smooth it out.
Top the pudding layer with the remaining Cool Whip and spread evenly.
Use a vegetable peeler or grater to create white chocolate shavings from the white chocolate bar and sprinkle them over the top.
Refrigerate the lasagna for at least 1 hour before slicing and serving.