In the bowl of a food processor fitted with the steel blade, place the Oreo cookies without the filling. Pulse until the Oreos are fine crumbs.
Place the cookie crumbs in a separate, medium-size bowl. Add the melted butter, and mix to combine, making sure all the cookie crumbs are moistened by the butter.
Press the mixture into the bottom and up the sides of a nonstick 9-inch springform pan.
It can be useful to use a tart tamper or the bottom of a small glass to press the mixture firmly into the pan.
If you don't have a springform pan, you can use a deep dish 9- or 10-inch pie plate, but grease it well.
Place the pan in the refrigerator to chill while you make the filling.
Make the filling.
In a small, heat-safe bowl, place the water and sprinkle the gelatin evenly on top. Mix to combine well, allow the mixture to sit for a few minutes until the gelatin swells.
Heat the mixture in the microwave at low power (about 50%) for about 30 seconds or until the mixture has just liquefied, but isn’t hot. Set the gelatin aside briefly.
In a large bowl with a handheld mixer or the bowl of a stand mixer with the paddle attachment, place the cream cheese and sour cream, and beat on medium-high speed until smooth and well-combined (about 2 minutes).
While still mixing on low speed, slowly pour in the gelatin mixture, and continue to mix until smooth. The mixture will seem relatively thin.
Add the salt and the (sifted) confectioners’ sugar and beat until smooth.
Place the Oreo cookies for the filling in a large ziptop bag. Hit the bag with a rolling pin or other blunt object to break the cookies into irregular pieces. Stop short of making the cookies into crumbs like for the crust.
Add the Oreo pieces to the bowl of filling.
Fold the cookie pieces into the batter with a spatula so they’re evenly distributed.
Pour the mixture into the prepared crust. Using an offset spatula, spread the filling into an even layer.
Chill the cheesecake.
Cover the pan tightly with plastic wrap, making sure the plastic doesn't touch the top of the cheesecake.
Place the covered pan in the refrigerator for at least 2 hours or until fully set. When the cheesecake is set, it will move only slightly when the pan is shaken from side to side.
Remove the pan from the refrigerator, remove the plastic, and free the filling from the sides of the pan by running a butter knife or offset spatula carefully all around the inside of the perimeter.
Serve.
Remove the sides of the pan, slice, and serve with more crushed or cut Oreos on top and some dollops of fresh whipped cream. Don’t add whipped cream to any slices that you think won’t be eaten the same day.
Notes
For the Oreos.The crust calls for 300 grams total of Oreo wafers, without the filling, which requires 70 individual wafer cookies (from 35 cookie sandwiches). I twist open each cookie, remove the filling using a butter knife or offset spatula, and discard the filling. If you'd like to use the cookies for the crust without removing the center cream of each cookie, just reduce the melted butter to 5 tablespoons, from 7.For the Oreos in the filling, I don't remove the filling. Those are crushed using a rolling pin without removing the creamy center.Nutritional information.Nutrition information is per slice, assuming the whole cake, without optional decorations, is sliced into 8 equal portions. It is an estimate made using online calculators, provided as a courtesy, and is inherently unreliable.