Mix 4 eggs and gradually add the parmesan until it is really thick. Depending on the size of the eggs, it can be a little less or a little more than 200 g.
Chop the onion and garlic and fry in a large pan with plenty of butter. Add the bacon and fry well.
At the same time, cook the spaghetti in salted water and drain, then add to the bacon in the pan and turn a few times.
Then pour the eggs with the parmesan on top and turn quickly several times so that the eggs do not stagnate.