Season the flour with plenty of salt, then coat the beef in it, shaking off the excess. Heat the oil in a large flameproof casserole dish and brown the beef on all sides until deeply golden, about 5-6 mins. Remove to a bowl. Pour 50-70ml water into the pan, scrape up any browned bits and pour into a bowl. Taste it – if it’s savoury and meaty, keep it; if it’s burned and acrid, pour it away.

Drizzle a little more oil into the pan, if needed, and cook the onions over a medium heat for 10-12 mins until lightly golden at the edges. Stir in the garlic, chipotle paste, tomato purée and all the spices. Cook for 3-4 mins until darkened and aromatic.

Pour in the tomatoes and reserved water, if using. Swill out the can of tomatoes and add that, too. Crumble in the stock cube, then bring to the boil. Return the meat to the pan and reduce the heat to a simmer. Cover the surface with a piece of damp baking parchment and cook on low for 2-3 hrs, adding the beans in the last 20 mins. The beef should be fall-apart tender. Leave to cool completely.

Meanwhile, make the pastry. Put the soured cream, mustard and 1 egg in a jug, and whisk to combine. Put the flour and a pinch of salt in a food processor, then scatter in the butter. Pulse to fine crumbs, then add the cheese and pulse again briefly to combine. Pour in the wet ingredients and pulse again briefly. Add 5-6 tbsp cold water in 1 tbsp increments until you have a soft dough. Tip onto the surface and knead gently. Divide in two, form into discs, then wrap and chill until needed.

When the chilli is completely cool, heat the oven to 200C/180C fan/gas 6 and bring the pastry out of the fridge 30 mins before using. Roll each pastry disc out into a thin sheet, about 1/2cm thick. Stamp out 12 circles using a 16cm round biscuit cutter (you may have to re-roll the offcuts).

Working with one piece of dough at a time, spoon a few tablespoons of the chilli below the centre of the circle, then top with a sprinkle of the mozzarella. Fold the top over and seal well, using a fork to crimp the edges. Beat the remaining egg and brush this over the pastry. Repeat with the remaining dough and chilli, then arrange over two large baking sheets lined with baking parchment. Bake for 25-30 mins until deeply golden and cooked through. Cool slightly and serve warm, or cool fully and pack for a picnic.