For the base, mix the crushed crackers and melted butter in a bowl until well combined. Press the mixture into the bottom of a 23cm/9in springform cake tin to form an even layer. Chill in the fridge for 20 minutes.
Preheat the oven to 180C/350F/Gas 4.
Meanwhile, for the topping, blend the cream cheese, sugar, eggs and vanilla extract in a food processor until smooth.
Spoon the topping mixture into a bowl and fold in the peanut butter.
When the base has chilled, spread the strawberry jam over it in an even layer, leaving a 2.5cm/1in gap free at the edges. Spoon over the topping mixture and spread evenly with a palette knife.
Bake the cheesecake in the oven for 50 minutes to one hour, or until the cheesecake springs back when pressed lightly in the centre with a finger and a skewer inserted into the centre of the cheesecake comes out clean.
When the cheesecake has cooked through, turn off the oven and leave the cheesecake in the oven to cool down (this will prevent it from cracking).