
Soak porcini in wine 30 min, strain and chop, reserve wine. Sauté onion, garlic and anchovy in oil and butter. Cook tomato paste, then cook mushrooms, porcini, salt, thyme and bay leaves 8 min. Add wine, reduce 6 min. Stir in flour, then chicken stock, simmer to thicken. Finish with pepper, parmesan and remaining butter.
Soak the dried porcini in red wine for 30 minutes to rehydrate. Strain, then squeeze the excess wine out of the mushrooms. Reserve the wine.
Chop the porcini finely (about 3mm/1/8").
Sauté - Heat the olive oil and melt 2 tablespoons of the butter in a large heavy-based pot over medium-high heat (~26cm/10.5"+). Add the onion, garlic and anchovy. Cook for 2 minutes, stirring regularly with a wooden spoon, until the onion softens.
Caramelise tomato paste - Add the tomato paste and cook for 2 minutes, stirring regularly.
Cook mushrooms - Add the sliced mushrooms first and cook for 2 minutes, so they reduce in volume a bit. Add the chopped mushrooms, porcini, salt, thyme and bay leaves. Stir and cook for 8 to 10 minutes, stirring from time to time, until the liquid released by the mushrooms is mostly gone.
Reduce wine - Pour in the reserved red wine and simmer for 6 minutes, stirring well at first to scrape up the fond at the bottom of the pot, then regularly towards the end. A path drawn with the spoon along the base should briefly hold.
Thicken sauce - Add the flour, stir well and cook for 30 seconds. Add the chicken stock, bring to a simmer and cook for 2 minutes, stirring regularly, until it thickens to a rich, gravy-like consistency.
Finish with the pepper, parmesan and remaining butter, stirring until everything is combined and the butter has melted through for a beautifully glossy finish. Put the lid on to keep warm while you cook the pasta.
Cook pasta - Bring a large pot of water to the boil over high heat. Add 1 tablespoon of salt and add the pasta. Cook per the packet direction minus 1 minute.
Reserve pasta water - Just before draining the pasta, scoop out one cup of pasta cooking water and set aside. Drain the pasta.
Toss - Add the cooked pasta and 1/4 cup of the pasta cooking water (the starch in the water helps the sauce stick to the pasta). Toss well on medium heat for 1 minute or until the pasta is all coated with the ragu and serve with a sprinkle of parmesan. Bon appétit!