For crust: In a food processor, crush Oreo cookies into a fine crumb. Pulse while adding butter until combined.
Pour crumbs out into a 9” pie plate and, using clean hands, push firmly and evenly along bottom and sides to create a crust.
For ganache: Heat heavy cream in a microwave-safe cup or bowl until hot but not boiling. Quickly remove from microwave and stir in chocolate chips. Continue stirring until chips are fully melted and mixture resembles a thick syrup. Allow to cool.
Pour 2/3 of ganache into the bottom of the pie crust and place in refrigerator to set-up while completing the remaining steps. Reserve the rest.
For mousse filling: In the bowl of a stand mixer, beat 1 cup heavy cream until stiff peaks form. Remove and reserve in refrigerator.
In the same bowl, beat together cream cheese and peanut butter until smooth. Slowly add powdered sugar until combined then add sweetened condensed milk. Continue mixing at medium-high speed until creamy and smooth. Occasionally scrape down sides/bottom of mixing bowl to ensure everything is mixed well.
Remove bowl from stand and with a clean silicon spatula, gently fold in ½ of the whipped cream. Once combined, fold in the remaining whipped cream until fully combined.
Gently pour into cool pie crust and smooth out the top. Drizzle remaining ganache over the top in both directions.
Using a toothpick or kabab stick, “swirl” the ganache in alternating circles to create a finished pattern across the top.
Place in refrigerator for a minimum of 3-4 hours to set.
For whipped cream: In a clean mixer bowl, beat together heavy cream, vanilla and sugar until stiff peaks form. Serve with pie.