Tip the flour into a bowl with 1 tsp salt and add the butter. Rub the butter and flour with your fingertips until crumbly. Add the eggs and 100ml cold water, bring together to a dough then turn out onto a floured surface and begin to knead until soft and smooth. Cover with cling film and put in the fridge to rest for 20 mins.
Remove the chorizo from its casing and add to a mixing bowl with the mince, onion, coriander, parsley, paprika, cumin and chilli flakes. Mix everything together, then cook in a frying pan over a medium heat for 2 mins. Add the tomato purée and cook for a further 7-10 mins until everything is cooked through. Remove from the heat and allow to cool.
Heat the oven to 180C/160C fan/gas 4. Divide the dough into four portions and roll out each one into a thin sheet. Use a 10cm biscuit cutter to cut out discs. Place 1 tsp of filling in the centre of each disc, wet the edges, pinch both sides up and fold in half to seal. Use a fork to crimp the edges.
Arrange on a lined baking tray, brush with beaten egg and bake for 20 mins. When the empanadas are ready, remove from the oven and cool for 5 mins before serving.