Take the cream cheese, sour cream, heavy cream, and eggs out of the fridge at least 1 hour before you begin. Preheat the oven to 325°F (160°C) with a rack in the center, spray the springform pan, and wrap the outside tightly in two sheets of heavy-duty foil. Set a kettle of water to heat for the water bath.
Pulse 24 Oreos (filling included) in a food processor until finely crushed, then stir with the melted butter until the mixture looks like wet sand. Press firmly across the bottom and about 1 inch up the sides of the pan, bake for 10 minutes, then cool on a wire rack.
Coarsely chop 15 Oreo cookies into pea-sized pieces, leaving some larger chunks for cookie bites, and set aside in a small bowl.
Beat the softened cream cheese on medium-low for 2 to 3 minutes until completely smooth, scraping the bowl. Add the sugar, flour, and salt and beat another 2 minutes, scraping once, until creamy and glossy.
Reduce the mixer to low and add the sour cream, heavy cream, and vanilla. Mix about 1 minute, just until blended with no streaks, then scrape the bowl again.
Keep the mixer on its lowest speed and add the eggs one at a time, mixing each only about 20 seconds until the yolk disappears and scraping between additions. Stop as soon as the last egg is blended to avoid cracks.
Fold the chopped Oreos into the batter with a rubber spatula using slow strokes, then pour over the cooled crust. Tap the pan on the counter to release air bubbles and smooth the top with an offset spatula.
Place the foil-wrapped pan inside the roasting pan on the center oven rack and pour in very hot water until it reaches about halfway up the side of the springform pan. Bake at 325°F for 65 to 75 minutes, until the edges are set and the center still jiggles slightly (about 150°F/65°C).
Turn the oven off and crack the door open about 2 inches. Let the cheesecake sit in the water bath inside the oven for 1 hour, then lift it out, peel off the foil, and cool on a wire rack about 30 minutes more until room temperature.
Cover the cooled cheesecake loosely with plastic wrap so it does not touch the surface and refrigerate at least 6 hours, preferably overnight. Do not remove the pan sides until completely cold and firm.
Chill a mixing bowl and beaters in the freezer for 10 minutes, then whip the cold heavy cream with the powdered sugar and vanilla on medium-high for 2 to 3 minutes until stiff peaks form. Run a thin knife around the edge, remove the springform ring, pipe rosettes around the top edge, and press one Oreo half into each rosette.
Dip a long, sharp knife in hot water and wipe it dry, then cut one slice. Clean and re-warm the knife before each new cut for neat, bakery-style edges, and serve the slices chilled straight from the fridge.