Preheat your oven to 220°C
Add the butter, granulated sugar, brown sugar, cinnamon, salt and water to a saucepan and place over a medium heat
Bring to the boil, take off the heat and set aside
Roll half your pastry to fit a 26cm or 9" pie dish
Place in the bottom of your pie dish and top with your apple pieces
Roll the rest of your pastry into a 10" circle and cut into 8 strips each 1" wide
Place the ends of your strips along one edge and begin to weave into a lattice pattern
Fold the ends of your strips under the edge of your bottom crust and either using your thumb or a fork, crimp to seal shut
Pour your mixture from the start of this recipe over the top of the pie taking care to fully coat the lattice - some should drizzle through the crust!
Bake for 15 minutes before turning the heat down to 175°C for approximately 35 to 40 minutes when the crust is golden brown, the caramel is set and the apple filling is bubbling
Leave to cool before slicing for a clean cut