Take 24 of the oreos and put them in a food processor. Pour in the melted butter and pulse until a very fine crumb forms. It should be somewhat like sand.
Transition this to a 9" pie or tart tin and press the crust down into the edges. It will feel like it wont come together at first, but continue to press and watch it form into a chocolate cookie crust. Set this aside.
Add the remaining 12 oreo cookies to the food processor and pulse again to form another batch of cookie crumbs, you also want these to be as fine as possible.
Using a stand mixer or a hand mixer (or a spatula and some strength!), beat the cream cheese until softened.
Heat up the heavy cream on the stove or in the microwave until it's hot but not boiling. In a heat-proof bowl, pour this over the chocolate. Whisk to melt the chocolate into the cream and create a chocolate ganache.
Add the remaining cookie crumbs, the ganache, the sugar, vanilla and the salt to the cream cheese. Beat or mix until everything is well combined and almost fluffy, about 3-4 minutes.
Pour the filling over the tart's crust and use a spatula to smooth out the top. Let this chill in the fridge for at least 30 minutes, but preferably an hour before serving.
To serve, top with whipped cream and a drizzle of melted chocolate, and enjoy chilled!