First prepare your vanilla wafer crust in 7 inch Spring form pan. Using melted butter, and your crushed vanilla wafers. Make sure the wafers are crumbled and fine. I use a ziplock bag to hand crumble and crush in the bag. Be sure to lightly spray the bottom of pan.Add the wafers, butter and sugar and mix well to form on the bottom. Place pan in the freezer while preparing the cheesecake mixture.For the filling, beat cream cheese and brown sugar in large bowl with electric mixer on medium speed until fluffy.Add eggs, one at a time, beating on low speed after each addition just until blended.Add pumpkin, flour, vanilla and pumpkin pie spice; beat until smooth. Pour into crust.Pour mixture into prepared pan, and place the pan on trivet. Cover pan with foil. Add a cup and a half of water to the pot. Lower pan and trivet in pot. Set to High Pressure Manual for 35-40 minutes. Let pot natural release. Gently remove cheesecake and trivet and set to cool. Place in refrigerator for 4 hours to let completely set until ready to serve.