I didn't make everything from scratch for this dessert, and I decided to live dangerously and serve it anyway. You do what you need to do - find a better, super healthy dessert, make your own homemade components of this one, or just go nuts and do it this way. An offset spatula is a handy tool for building this dessert, if you have one.
Oreo Ice Cream Dessert
1 pkg. regular Oreos
3 tbsp. butter, melted
1 1/2 gallon container chocolate ice cream, softened
1 1/2 gallon container vanilla (or cookies & cream, or mint chip), softened
1 jar of fudge sauce (I grabbed Mrs. Richardson's)
1 container Cool Whip
Line a 9" x 13" baking dish with foil or parchment. Set aside. Process 30 Oreos (the whole cookie - none of this scraping out the filling business) in your food processor to get a fine crumb mixture. Add in the melted butter, pulse to combine. Pat the crumb mixture into your baking dish. Layer 1, check. Crunch up the rest of the cookies into rough pieces and set aside.
Spoon chocolate ice cream onto your cookie crust and carefully spread, so as not to totally wreck the cookie crust. You can also slice a brick of ice cream, and arrange the slices over the crust, and sort of mold them into place, as well - you pick. I just scooped and spread. Freeze for at least 15 minutes. Layer 2, check.
Heat your jar of fudge sauce (or your homemade goodness) so it will spread, and spoon onto your chocolate ice cream layer. Work sort of quickly, as the ice cream will start to melt into the hot fudge, but it's not the end of the world. Then stick it back in the freezer for another 15 minutes or more. Layer 3, check.
Spread the vanilla ice cream (or cookies & cream, mint chip, etc.) on top of the fudge layer (and some people added an extra layer of cookie crumbs here, but it's really not necessary) quickly. Then, you guessed it, stick it in the freezer. Layer 4, check.
Finally, spread the whipped topping on your vanilla layer, sprinkle the remaining cookie crumbs over top, drizzle with some remaining hot fudge sauce, cover the whole thing, and stick it in the freezer. Freeze overnight if possible, and then remove from the freezer about 10-15 minutes before you serve it so you don't need a chainsaw to cut pieces. You should be able to lift it out of the pan with the foil, and cut. It should serve anywhere from 12-24 people, depending on how wild you get with your serving sizes.