To prepare the ragù

• Heat the oil in a large casserole pot. When hot, add the finely diced onion.
• Stir, season with salt, cover with a lid and turn down the heat to low.
• Allow to sweat, stirring regularly, until the onion has become translucent and is completely tender. This process will take about 10 minutes.
• Add the finely diced carrot and celery to the pot, stir to mix and continue cooking for a further 5 minutes to soften the vegetables.
• Increase the heat and mix in the bacon lardons.
• Sauté over a medium heat until the fat renders out and the bacon becomes lightly coloured.
• Increase the heat to high and add in the beef and pork mince. Brown the meat, stirring regularly until the meat loses its pink colour.
• Season, stir in the tomato purée and then pour in the white wine. Boil the wine until it has reduced almost to a glaze.
• Add the bay leaves, rosemary sprigs and stock, bring up to the boil and then turn down the heat to the very gentlest simmer.
• Allow to cook for about an hour or until reduced by at least half.
• Bring the milk to a simmer and add to the meat.
• Cover the sauce with a lid, leaving it slightly ajar, and continue cooking for a further 30 minutes or so at a gentle bubble, adding more stock if the ragù becomes too dry.
• Remove the bay leaves, the sprigs of rosemary (or the rosemary needles if they have fallen off) and discard.
• The sauce will keep in the fridge for 3 or 4 days or for a number of months in the freezer.

To prepare the pasta

• Bring a large pot of pasta water with about 4 litres of water to the boil.
• Add 1½ tablespoon salt and return to the boil.
• When the tagliatelle is cooked about 90% through, drain, holding back some of the pasta water.
• Meanwhile, heat the ragù in a frying pan and bring to a gentle simmer.
• Add the butter and swirl to combine.
• Add in a good dash of pasta water and the pasta.
• Simmer until the sauce coats the pasta loosely.
• Towards the end, mix in a fistful of Parmesan and grate some more to bring to the table.