Preheat the oven to 350F/176C. Line an 8x8" baking pan with parchment paper, or aluminium foil. Set aside.
Process the Oreos in a food processor until finely crushed. Add the melted butter and pulse until evenly combined. Press the mixture into the prepared pan.
In a large mixing bowl, using a hand or stand mixer fitted with the paddle attachment, beat the cream cheese, condensed milk, and peanut butter until smooth. Mix in the vanilla and salt. Pour the mixture over the Oreo crust, and spread out evenly. Bake for 15 - 18 minutes, or until set. Allow to cool completely in the pan on a wire rack.
For the Glaze
In a saucepan, melt the butter, and chocolate over medium heat until smooth. Pour over the cooled cheesecake and refrigerate until set. Cut into bars, and serve!