Place a large pot with water on high heat and bring to the boil. Add a pinch of salt and Fettuccine pasta to the boiling water and cook until ‘al dente’, referring to the cooking time specified in pasta packet instructions.
Meanwhile, heat the butter and olive oil in a large frying pan over high heat. Once the butter has melted, add the garlic and cook, without browning for 1 minute. Add the mushrooms, thyme and seasoning to taste. Cook the mushrooms for 3 minutes over high heat, then reduce the heat to low. Discard the garlic clove.
Drain the pasta, reserving 150ml (one ladleful) of the pasta cooking water.
Add the pasta, pasta cooking water and Parmigiano Reggiano to the frying pan with mushroom butter sauce. Toss well over the heat until the cheese melts and forms a smooth sauce (approximately 2 minutes).
Remove from the heat. Grate ¾ of the Truffle on top of the mushroom pasta using a truffle slicer. Alternatively, using a very sharp knife to carefully slice as thin as possible. Toss to combine.
Tip: I would recommend using Truffle within 5 days to fully enjoy its aroma and flavour. The ideal storage is in the refrigerator, wrapped in a small piece of paper towel (change paper towel daily) and placed in a glass container. Remove it from the refrigerator at least an hour before using for the Truffle to release all its aroma.
Divide portions of Truffle mushroom pasta among deep serving bowls. Top with a grating of the remaining Truffle. Serve immediately – buon appetito!