Method

• 1.
  For the pasta, place egg yolks and flour in the bowl of a stand mixer fitted with the dough hook. Mix until combined and smooth. Cover and rest for 30 minutes.
• 2.
  Cut the dough into 4 pieces, cover and set aside. Using a pasta machine, pass each piece of dough through the machine, starting at the widest setting and working down to the thinnest. Repeat this process for all 4 pieces of dough. Cut the sheets into 20cm-long pieces and stack them on top of each other. Roll them up and cut into 2cm-wide noodles. Dust with flour and store either in nests in the fridge, or dry by draping them over a rack.
• 3.
  To make the mushroom ragu, heat half of the olive oil and half of the butter in a large frypan over high. Reduce heat to low, add onion, pancetta and garlic and cook, stirring frequently, for 6-8 minutes until onion is translucent. Strain, reserving oil, and set onion, pancetta and garlic aside.
• 4.
  Add the remaining 30ml oil, reserved oil and 75g butter to the frypan and place over high heat. Drain the porcini, reserving liquid. Chop porcini and add to pan with chestnut mushroom. Cook, stirring occasionally for 5-6 minutes until softened and coloured. Return the reserved pancetta mixture to mushroom mixture and toss to combine. Season to taste. Add the wine, scraping the bottom of the pan with a wooden spoon and reduce the wine by one-third. Stir in thyme sprigs, reserved porcini liquid and chicken stock. Bring to the boil, reduce heat to medium and simmer for 8-10 minutes until sauce is thickened. Season to taste and set aside and keep warm until ready to serve.
• 5.
  Meanwhile, bring a large saucepan three-quarters full with salted water to the boil. Make sure the mushroom ragu is next to the saucepan and hot. Cook the pappardelle in 2 batches, stirring gently to separate pasta, for 1-2 minutes. Remove using large tongs and immediately add to the mushroom ragu. Toss well to combine. If the pasta looks too dry you can add a little of the cooking water. Scatter with cheese and extra thyme to serve.