Adjust the oven rack to the lower-middle position. And preheat the oven to 350°F (180°C,) or 160°C for a fan oven.
Lightly grease a 9-inch (23 cm) springform pan with butter, then line it with parchment paper (bottom and sides).
Wrap the outside bottom and sides of the pan with two layers of heavy-duty foil (18 inches wide) to prevent any water from leaking into the crust while baking. Set aside.
Put 24 Oreos in a food processor, and blend until finely chopped. On low speed, slowly pour in the melted shortening until well mixed.
Press the cookie crumb mixture into the bottom of the springform pan and slightly up the sides of the pan. Bake in the preheated oven for 10 minutes. After the crust is done baking, lower the oven temperature to 315°F/160°C.
While the crust is baking, combine the softened cream cheese and sugar in a large bowl, and blend with an electric hand mixer on medium speed until smooth and creamy. Blend in the sour cream, flour, and vanilla extract at low speed until well combined. Mix in the eggs and yolk one at a time with an electric hand mixer on low speed. Carefully fold in the crushed Oreos.
Pour in one third of the cheesecake filling into the baked crust, spreading to the edge of the pan with a spatula, then place the 12 whole Oreos in a single layer over the filling. Pour in the rest of the filling over the Oreos, and spread to the edges.
Place the springform pan in a 12x16 roasting pan. Fill the outside pan with water that’s one to two inches deep or about halfway up the springform pan.
Bake the cheesecake for 60 to 70 minutes or until the center of it is set. Turn off the oven, open the oven door slightly, and put a wooden spoon the door to keep it cracked open. Let the cheesecake rest in the oven for another hour.
After an hour, take the cheesecake out of the oven and place it on a cooling rack to rest until it reaches room temperature, about an hour.
Run a knife between the sides of the cheesecake and the springform pan to slightly loosen it. Refrigerate for 4 hours or overnight. Top with a layer of whipped cream, crushed Oreos, or mini Oreos. Serve chilled.