For the dough, put the flour, paprika, yeast, oil, 300ml lukewarm water and a large pinch of salt in a bowl. Mix into a soft, slightly wet dough. Knead in a stand mixer fitted with a dough hook or by hand for 10 mins until smooth (it will still be quite soft). Tip into an oiled bowl, cover and leave to rise for 2 hrs.
Meanwhile, make the filling. Fry the chorizo in a large saucepan over a medium heat for 2 mins until some of its oils have been released. Add the garlic and continue to fry for 30 seconds. Add the passata, sugar, vinegar and preserved lemons, and simmer for 5 mins until thick. Stir in the basil and rocket. Leave to cool.
Heat the oven to 200C/180C fan/gas 6 with a baking sheet inside. Divide the dough into four pieces, then roll each out on a lightly dusted surface to a thin 30cm circle. Lay each circle on a square of baking parchment dusted with semolina. Spread the cooled filling over half of each circle, leaving a border, then top with some of the mozzarella. Brush around the edge of each circle with a little water. Working with one circle at a time, fold one half over the other so the filling is enclosed, then crimp the edge to seal. The calzones can now be frozen for up to three months (see below). Lift the calzones on the parchment squares onto the hot baking sheet in the oven, sprinkle the parmesan on top, and bake for 15-20 mins until puffed up and golden brown.
Wrap the unbaked calzones in the baking parchment, then a layer of foil, before putting in the freezer.