Heat some oil in a large saucepan and fry the mince until it has changed colour. Drain and put it in a bowl.
Thinly slice the leek and cut the bell pepper into small cubes. Chop the garlic.
Pour away any liquid from the pan and add more oil. Gently sauté the leek and red pepper for about 8 minutes, then add the garlic and stir for a minute. Add the mince, then stir in the oregano, chipotle, tomato paste, cumin and paprika. Add a drop of water and season to taste. Put a lid on and cook for 10 minutes.
Drain the beans or lentils and stir in the mixture. You should have a thick ragu - it shouldn’t have any liquid. ( if there is, turn up the heat and reduce it completely).
Stir in the coriander leaves, then let it cool.
Make a coffin template using a cardboard - about 15 cm long.
Preheat the oven to 190°C.
Cut out the coffins, you should be able to have 8 per pastry sheet.
Put half of them onto a baking sheet, lined with parchment paper.
Cut out crosses in the remaining coffins - using either a template or a small ruler. These will be the lids.
Spoon some filling onto the coffin bases, then brush the edges with egg. Carefully put the lids on top and push the two pastry sheets together with a small fork.
Brush the pastry with egg or milk and bake for 12-15 minutes until golden.