Prepare the pan: Spray the 7-inch cheesecake pan with nonstick cooking spray. Crush the Oreos - I put them in a gallon zip-top bag and pound them with a rolling pin. Spread the Oreo crumbs evenly across the bottom of the pan and pack down, pushing the crumbs up the sides a little.
Make the cheesecake filling: Soften the cream cheese by leaving it out at room temperature for at least 1 hour. (Or soften the cream cheese in the microwave, 30 seconds to 1 minute). Beat the cream cheese in an electric mixer on medium speed until smooth, about 1 minute. Slowly add the sugar and beat on medium speed until the sugar is completely blended, about 3 minutes. Stop the mixer and scrape down the sides. Add the vanilla and sour cream and beat on low speed until completely blended, about 1 minute. Stop the mixer again and scrape down the sides. Add the eggs one at a time, beating each on low speed until just blended. (Don’t over-beat the eggs.) Stir in the 5 rough-chopped Oreos by hand. Pour into the cheesecake pan.
Pressure cook the cheesecake for 20 minutes with a natural pressure release: Put 2 cups of water and the cooking rack in the pressure cooker pot. If you don't have a rack with handles, make an aluminum foil sling to lift the cheesecake: fold a 2-foot long piece of aluminum foil over a few times, until it is a long strip about 4 inches wide. Center the cheesecake pan on the sling and carefully lower it into the pot, setting it on the rack. (Bend the edges of the foil sling over so they fit under the lid.) Lock the lid on the cooker and pressure cook on high pressure for 20 minutes in an electric PC (use Manual, Pressure Cook, or Pressure Cook - Custom mode in an Instant Pot), or for 16 minutes in a stovetop PC. Let the pressure come down naturally, about 20 more minutes. (If you’re in a hurry, you can quick release any pressure left in the pot after 15 minutes.)
Cool the cheesecake, then serve: Lift the cheesecake out of the pressure cooker. Loosen the cheesecake from the sides by running a paring knife around the edge of the pan. Cool the pan at room temperature for an hour, then refrigerate for at least 4 hours, preferably overnight. Just before serving, set the 8 half-cookies in a ring around the outside edge of the cheesecake, cut side down, pointing towards the center. (See the picture at the top of this post. This gives you one cookie per piece of cheesecake.) Slice the cheesecake into 8 pieces and serve.