Cut the Lardo di Colonnata into thin slices and then into irregular, small pieces. Wash the champignon mushrooms and dice them.
In a wide, low saucepan, sauté the crushed garlic clove until it turns golden. Remove the garlic, then add the pork fat and the mushrooms. Pour in the tomato sauce. Flavour with a pinch of salt and cook for a few minutes.
Flake the tuna with your fingers and add it to the sauce. As soon as it begins boiling again, remove the saucepan from the heat.
Cook the Barilla Spaghetti in plenty of salted water. Drain when al dente and sauté on high heat in the frying pan with the sauce. Grind the pepper and sprinkle everything with the chopped parsley. Serve the Spaghetti steaming hot with a generous sprinkling of Parmigiano Reggiano.