Sift flour and salt together in a bowl and make a well in the center. Add small amounts of the chilled water and mix until the dough is soft but not sticky. Turn out on a lightly floured surface and knead until it all comes together consistently.
Lightly oil your surface and roll out your dough as thin as possible . You also want to roll it out long as you can and not too wide. Smear the softened butter evenly over the dough.
Starting from the end closest to you, stretch and roll the dough upwards. Continue to stretch and roll the dough. If the dough gets long and thin at the sides, just fold it into the middle and keep rolling. This will just end up creating more layers in the pastry. Once you have finished rolling it, place it on a plate, cover it with glad wrap and leave it in the fridge for 24 hours.
Mash all the filling ingredients together until really well mixed. After 24 hours, place dough on a lightly floured surface and cut into thick slices about 2 cm wide. Stretch the outer edges of each section until you have an oval shape. Try not to press down on the dough as it inhibits it becoming flaky.
Place dough in the palm of your hand and fill with your chosen filling. Stretch the sides out. Press sides together all the way around. Pinch the ends flat and gently push inwards to shape the Pastizzi. Bake on a baking paper lined tray at 220 until golden brown for about 20 minutes. Rest 5 min