Preheat oven to 350 degrees F. Place 5 tablespoons of butter in an oven safe casserole dish or baking pan. I used a 9x13 dish for a thinner bar - you could also use an 8x10 pan with foil if you like your bars a little thicker.
Place the dish with butter in the oven just until butter is melted. Remove dish from oven. You can also use cooking spray.
Take 2 sleeves of the oreos (I used double stuffed so that was about 20 cookies for me) and crush them. I used a food processor because I wanted the oreo crumbs fine like graham cracker fine crumbs. This is the crust of your bars.
Sprinkle the oreo crumbs evenly over the melted butter and press until you have one fairly even layer.
Sprinkle chocolate and butterscotch chips over oreo crumb layer. DO NOT mix.
Pour sweetened condensed milk over everything in the pan.
Crush about 5-6 more oreos. You can do this by hand. If you do this in the food processor, just pulse it. You don't want crumbs this time, you're aiming for small chunks.
Sprinkle chunks of oreos and oreo crumbs evenly over the bars.
Bake at 325 F for about 20 minutes. You know its done when the edges are a tad brown and the rest will be nice and bubbly.
Remove from the oven and allow to cool completely at least 15 minutes to 30 minutes. Cut into bars. Enjoy!
Notes
You are going to be so glad you made these tasty magic bars!