Put the flour and butter into a bowl. Rub together quickly and efficiently until you have something resembling fine breadcrumbs. You can do this by pulsing in a food processor, if you prefer.
Add the egg yolk (reserve the white for later) and 4 tbsp of cold water. Cut the liquid through the crumb with a cutlery knife. If it still seems really dry, add another drop or two of water, but try not to add more as a wet dough may result in a tough or soggy pastry.
Gather the pastry into a ball and knead only as long as it takes to get a smooth, even texture.
Wrap and place in the fridge to rest.
Make the filling
Put the potatoes in a pan of cold water. Boil for 10 minutes until just tender. You don’t want them too soft or they’ll break apart when added to the mix. Drain and set aside to cool.
Put the oil and butter in a pan over a medium heat.
Once the butter is melted, add the onions and cumin and fry for 5 minutes until soft and browning.
Put the cheese in a bowl with the chutney, parsley, fried onions and a pinch of salt and pepper. Stir together.
Chop the potatoes into small 1/2cm (half inch) pieces. Add to the bowl and stir through.
Make the pasties
Line two baking trays with baking paper.
Lightly flour your work surface and work with half of your pastry at a time. Roll the pastry out to about 3mm (⅛ inch).
Cut out rounds using a 10cm (4 inch) cookie cutter or upturned small bowl. In total, using all the pastry and re-rerolling where necessary, you should get 16-18 rounds in total.
Put a spoonful of filling mixture in the centre of each disc of pastry. Bring the sides together and pinch together at the top to form a classic pastie shape.
Place the pasties on the lined baking trays.
Brush with egg white and sprinkle with milled black pepper.
Cook in the oven at 220C(200C/430 fan) for 18 minutes until golden.
Serve with salad, fresh green veg, pack into your lunchbox, or enjoy in whatever way takes your fancy.