Preheat oven to 180 degrees C. Line a 8×8 inch baking pan with baking paper or foil. Lightly coat with cooking spray.
Pulse cookies in food processor until fully ground, continue pulsing while gradually streaming in melted butter until incorporated. Press mixture evenly into prepared baking pan. Bake 10 minutes. Set aside and allow to cool about 10 minutes.
Using an electric mixer on medium speed, beat together cream cheese and sugar until smooth. Mix in peanut butter, then eggs, one at a time; beat together until smooth. Add vanilla, salt and flour, beat until just combined.
Pour evenly over prepared crust. Place pan on large rimmed baking sheet, and place in oven on centre rack. Pour hot water into baking sheet until almost full. Bake for about 40-45 minutes, until set around the edges, but still slightly jiggly in middle.
Remove 8 x 8 inch pan and cool completely on rack. Once cool cover and chill until firm, at least 3 hours.
Using the baking paper overhang, lift cheesecake out of pan and cut to desired size.