To make the pastry, stir together the flour, salt and sugar in a medium-sized bowl. Cut the butter into cubes and toss through the flour, rubbing briefly with your fingers to combine. Add 100-120ml of very cold water to the bowl and stir, then knead until a smooth dough forms - you may need a little more water depending on your flour.

Roll out the dough on a lightly floured surface into a rectangle, approximated 20x30cm. Grate half of the frozen butter over the lower two-thirds of the dough. Fold down the top third then fold the bottom third up as if you were folding a letter.

Turn the dough 90° and roll out again. Grate over the remaining butter and fold again as above. Wrap in clingfilm and refrigerate at least 30-45 minutes.

Meanwhile, make the filling. Heat the oil in a large frying pan and cook the onion gently for 5 minutes until softened, but not browned. Add the mince and cook until coloured, then add the red pepper and garlic. Add the beef stock, sugar chilli, cumin, oregano and cinnamon, then cook, stirring occasionally for 5 minutes. Season to taste with salt and pepper, then set aside to cool.

When the dough has chilled, roll it out on a lightly floured surface and cut out 16 x 10cm diameter rounds. You will probably need to use the scraps and re-roll them to get the full amount. Spoon one tablespoon of the filling onto each pastry round. Beat the egg and milk together, then brush half of the border with the egg wash. Fold the pastry over to seal and use a fork to press the edges together.

Place the empanadas in the fridge for 20 minutes to firm up. Meanwhile, line a tray with baking paper and heat the oven to 180°C / 350° F / Gas 4.

When the empanadas have chilled and the oven is hot, place the empanadas on the baking tray. Cut a small slit in each to allow air to escape, then brush evenly with the remaining egg wash. Bake in the preheated oven for 30-40 minutes until golden brown.

Serve warm with salsa or sour cream swirled with chilli sauce for dipping.