For the pastry, mix together the flour, paprika and salt in a bowl and rub in the butter using your fingertips. Add 2-3 tablespoons of cold water - enough to bring the mixture together as a dough. Wrap the pastry in cling film and leave to chill in the fridge.
For the filling, wilt the spinach with a splash of water in a pan over a medium heat. Remove and strain the spinach. Set aside to cool. Tip the spinach into a bowl and add the cheese, nutmeg, salt and freshly ground black pepper.
Preheat the oven to 200C/fan oven 180C/400F/Gas 6.
Roll out the pastry. Cut out circles of pastry the right size to fit your tartlet tin and line the tray with the pastry. Prick the base of the tarts with a fork. Place in the freezer until frozen.
Make parcels of baking parchment filled with dried split peas (that are the right size to fit inside the tartlets) ready for blind baking the pastry cases.
Blind bake the pastry for 10 minutes and then reduce the temperature to 180C/fan oven 160C/350F/Gas 4. Remove the parcels of baking parchment from the cases, brush with egg white and bake until golden-brown.
Part-fill the tart cases with the spinach mixture. Crack a quails’ egg on top of each case. Bake for 8-10 minutes at 180C/fan oven 160C/350F/Gas 4.
Sprinkle the tarts with paprika. Serve.