To make the pasta, place the flour in a bowl or on a wok surface, and make a well in the centre. Add the egg, yolks, half olive oil and a pinch of salt.
Firstly with a fork and then with your hands, gradually mix the flour with the eggs and oil until you obtain a rough paste.
If necessary, add a splash of water. Knead the dough on a lightly floured surface for a few minutes until smooth, not sticky. Cover with a cloth and leave to rest for 15-30 minutes.
Roll your fresh pasta into a very thin flat sheet and then into a loose sausage shape. Cut across the sausage with a sharp knife to make thin strands, about 3–4mm wide, and leave to rest on a bit of a clean cloth.
To make the sauce, melt the butter in a pan, add the onion and cook for about 5–7 minutes, until it starts to turn golden. Add the chicken livers, stir them around in the hot butter and fry for 3–4 minutes.
Add the drained porcini, tomato purée and Marsala, stir to combine and season to taste. If the sauce appears too thick, add up to 4tbsp of the porcini-soaking water.
Meanwhile, cook the pasta in plenty of lightly salted boiling water until al dente, then drain and mix with the sauce. Stir in the truffle oil and sprinkle each serving with freshly grated Parmesan and the truffle slices, if using.
First published in Two Greedy Italians Eat Italy by Antonio Carluccio and Gennaro Contaldo, published by Quadrille (£20, hardback). Photograph: ©David Loftus