Butter a 20cm springform cake tin and line the base with greaseproof paper. Blitz the biscuits and the pretzels in a food processor and mix the biscuits with the melted butter. Place the tin on a tray and bake for 10 mins, remove from the oven to cool
Add the cream cheese into a bowl with 3 tbsp of the caramel sauce, the vanilla, sugar and flour, and beat until smooth (this is easiest with an electric whisk)
Beat in the eggs, one at a time, until the mixture is think and smooth – it will look custard like
Pour the mixture over the biscuit base and cook in the over for 10 minutes
Reduce the temperature to 140C/120C fan/gas 1 and continue to bake for 25-30 mins until there is a slight wobble in the middle
Turn off the heat and with the door ajar leave the cheesecake to cool. Leaving the cake in the oven overnight is ideal. Once cooled keep in the fridge until needed. (If you put into the fridge while it is still warm it is more likely that the top will crack)
When you are ready to serve remove the sides of the tin (You may need to run round the edges with a knife).
Spread the remaining salted caramel sauce over the top of the cheesecake. You can add any further decoration that you would like at this point, in mine I have covered in toffee popcorn and pretzels (don’t add these too early as they will go soggy after sitting in the fridge overnight)