Place Oreos in a food processor and process until they’re a fine crumb.
Mix crumbs and melted butter in a large bowl. Stir using a fork, then press into a 9x13-inch pan.
Chill until ready to fill.
Beat cream cheese, powdered sugar, and peanut butter in a large bowl until smooth.
Fold in one container Cool Whip.
Add pudding mix and milk to a large bowl or measuring cup.
Whisk until no lumps remain and let sit for a few minutes to thicken.
Remove crust from the refrigerator. Carefully spread the peanut butter mixture evenly over the crust.
Spread the slightly thickened pudding over the top of the peanut butter layer.
Top with remaining cool whip and spread evenly.
Top with hot fudge and/or chopped peanut butter cups.
Chill at least one hour before serving. Can be made up to 24 hours in advance. Leftovers will last about 3 days in the refrigerator.