Thaw the spinach. Heat the milk.
Crumble the yeast into the milk and add 1 tsp salt.
Wash the parsley, pat dry and finely chop the leaves. Add to the milk, reserving 2 tbsp.
Mix the flours, add to the yeast milk and mix to a pliable dough.
Cover the dough and leave to rise in a warm place for 30-40 minutes, until doubled in size.
Meanwhile, wash, peel and coarsely grate the potatoes.
Drain the spinach and chop finely. Peel and finely dice the onion.
Toast the pine nuts in a dry pan until lightly golden. Remove and set aside.
Heat the oil in a pan and fry the onion over a medium heat until softened.
Add the potatoes and spinach to the pan and cook until the liquid evaporates. Add the remaining parsley and paprika, and season with salt and pepper.
Crumble the feta cheese. Add cream cheese and feta cheese to the spinach, gently mix and leave to cool.
Knead the dough again. Divide into 8 portions and roll out each one to a 12cm round.
Add some potato and spinach mixture to each round, sprinkle with pine nuts and fold in half to enclose the filling.
Press the edges well to seal and brush with condensed milk to glaze.
Place the calzones on a baking tray lined with baking paper and bake in a preheated oven at 200°C (180°C fan, gas 6) for 20 minutes.