First wash the lemons well with a toothbrush under running water, then remove the skins from 2 of the 3 lemons with a potato peeler (without taking the white part) and leave them to infuse in the water overnight.
Wash the leaf, dry it and let it dry for 2 minutes in the microwave at maximum power, then chop it to reduce it to dust.
Grate the peel of the third lemon and grate the cheese too.
Drain the skins left in the infusion while preserving the water.
Pour the water into the pan and bring it to a boil with a little olive oil and a little salt.
Lower the spaghetti and cook, adding more water only if necessary (consider that the spaghetti should not be drained, the water should be absorbed completely, as if it were a risotto).
At the end stir in the cheese and season with the grated lemon peel
Serve the lemon noodles ready, decorate with the powdered leaves and serve.