The filling needs to be cooked until it is this consistency 
I don’t have permission to share this recipe but there are many on the internet. I made the filling using the bread machine function which I found easier as I don’t have patience to stand and stir for 45mins.
The pineapple filling was a tart and a lovely contrast to the buttery pastry. Something I will definitely make again. I made myself a chef’s treat using a piece of fresh pineapple and it was very nice, next time I will cover fresh pineapple with the pineapple filling and wrap with pastry for my chefs treat.