Heat the oil in a large, deep-sided frying pan. Over medium heat, gently cook the onions for 5 minutes until they begin to colour golden and soften. Add the carrots to the pan and cook for another 5 minutes, stirring occasionally.

Add the beef mince to the pan, season with a little salt and pepper and cook, breaking the mince up with a wooden spoon, until it has begun to colour. Stir through the rosemary and flour. Pour the red wine into the pan and allow to bubble up.

Stir together the beef stock, Worcester sauce and tomato paste, then add to the pan along with the lentils. Bring to the boil, then turn the heat down and simmer for 30 minutes, stirring occasionally. Check after 15 minutes and add up to 250ml more water, if the mixture is getting too dry.

Season to taste, then set aside to cool. Meanwhile, cook the potatoes in boiling salted water until fork-tender, drain then set aside.

To make the pastry, place the flour, butter, salt and sugar in the bowl of a food processor with the blade attachment fitted and pulse until the mixture resembles fine crumbs. Add the egg to the mixer and process until the dough begins to clump together, adding a tiny bit of water only if absolutely necessary.

Turn the dough out onto a lightly floured surface, knead briefly until smooth, then form into a log. Divide into 6 even pieces. Lightly grease a 6 hole, 250ml / 1 cup capacity ‘Texas’ style muffin pan (for 1 large pie, see notes). Roll each piece of pastry out to a round, about the same size as a saucer, then press gently, but firmly into the prepared tin, trimming the edges. You will have a little pastry left over, this can be frozen until needed. Place the muffin pan in the fridge while you heat the oven.

Heat the oven to 200°C / 400°F / Gas 6 with a rack in the lower third. Meanwhile, mash the potatoes with the butter and milk and season well with salt and pepper. When the oven is hot, take the muffin pan from the fridge, divide the cooled filling between the pastry cases, spoon the masked potato onto the top and use a fork to create ridges on the potato. Bake in the preheated oven for 30-40 minutes until the potato is starting to crisp and brown.

Allow to cool in the tin for 5-10 minutes before twisting gently to loosen. Tilt the pan to help you lift out the pies. Serve immediately.