Prepare the White Alba Truffle: Remove the White Alba Truffle from the refrigerator shortly before serving. Brush it gently under a light stream of cool water to remove any soil, then pat it completely dry with kitchen paper. Clean the truffle only when ready to use it.

Bring the pasta water to the boil: Fill a large pot with well-salted water and bring to a rolling boil.

Melt the butter: While the water heats, place the cold diced butter in a wide pan large enough to hold the cooked pasta. Melt gently over low heat, then remove from the heat.

Cook the fettuccine: Add the fettuccine to the boiling water and cook according to the packet instructions until al dente. Before draining, reserve some pasta cooking water. Drain the pasta well.

Emulsify the butter sauce and toss the pasta: Return the pan with the melted butter to medium heat. Add a splash of reserved pasta cooking water and bring it to a gentle simmer. Add the drained fettuccine and toss vigorously until coated in a smooth, glossy sauce. Add more pasta water, a little at a time, if needed. Taste and adjust with fine sea salt and freshly ground black pepper.

Shave the truffle and serve: Divide the fettuccine among warmed bowls. Shave the fresh White Alba Truffle finely and generously over each portion, then serve immediately.