Mix the cream cheese with the sugar and vanilla with a stand or handheld mixer with the whisk attachment until really smooth. Every once in a while stop to scrape the sides with a spatula so you know everything is getting mixed in.
Add the sour cream and salt and mix some more.
With the speed on minimum add the eggs one by one. You know you can add the next egg when the previous one has mixed in.
Add the dulce de leche and mix it but carefully and only until it looks marbled.
Put the filling in the mould and take to a preheated oven at 150C.
Cook for 20-30min or until it jiggles like gelatin if you move it.
Wait for it to cool down completely and leave in the fridge overnight or at least 8 hours.
On the next day unmould the cheesecake and spread the extra dulce de leche on top. Use a damp knife to cut the cheesecake bars. Mine were 5cm wide. Make sure you clean the knife in between cuts so your bars stay nice and clean.