Wash the mushrooms thoroughly to get rid of dirt.
Place in a bowl with 1l water at room temperature and leave to soak for at least 30 minutes.
Take out the mushrooms with a blotted spoon and wash again to eliminate the remaining dirt. Strain the soaking water and reserve.
Cut the larger mushroom into halves or quarters.
Melt 30g butter in a medium sized pan.
Add the shallots and mushrooms and fry for 5-7 minutes until caramelized.
Hit the pan with the chicken stock and bring to simmer. Add the garlic, thyme, soaking water and a splash of red wine vinegar and cook over low heat for at least 20 minutes. Add more soaking water if the liquid evaporates. Discard the thyme sprigs.
In the meantime, prepare the persillade by mixing together 1/2 cups chopped parsley, minced garlic clove, 1 tbsp lemon juice, 1/2 tsp salt and 1 tbsp truffle oil.
Add persillade to the mushrooms for the last 5 minutes of cooking.
Boil the pasta just short of al dente. Reserve 1/2 cups of cooking water. Drain, return to the pot and add the mushrooms mixture. Stir to combine and loosen with cooking water.
Serve sprinkled with fresh parsley and parmesan and an extra drizzle of truffle oil.