1) Pour the flour into a fountain on the work surface and create a dimple in the center. Shelled the eggs, one at a time, and slide them gradually to the center of the fountain. United a pinch of salt and lightly beat the eggs with a fork to mix the yolks with the whites. Jumbled up with your fingertips, gradually incorporating the flour. Knead for at least 10 minutes, then form a ball, wrap it in plastic wrap and let it rest for 30 minutes.
2) Peel the onions, slice them and transfer them to the baking tray lined with baking paper. Salt, pepper, add the bay leaves, a drizzle of oil and bake at 200 ° for 20 minutes, turning them a couple of times.
3) Divide pasta in 4 portions, flour them on the work surface and pass each one through the rollers of the appropriate machine, gradually reducing the thickness until a thin sheet of about 2 mm is obtained. Obtained then the noodles by placing the appropriate die in the machine.
4) Dissolve butter with sage leaves, cinnamon, a pinch of salt and a grind of pepper.
5) Meanwhile cook the pasta in boiling salted water for 2-3 minutes, drain it al dente and transfer it to a large bowl: unite still hot onions (remove the bay leaf) and cinnamon and sage butter. Complete with grated Parmesan cheese and serve.