In Italian one can make a passive construction by adding the so-called "si passivante" to the third person singular or plural form of the verb. Albeit I'm not sure if the following definition makes sense to/for an English mother tongue, literally the "si passivante" is the "si" that makes the verb passive.
Italians, especially if they are high educated people, generally prefer impersonal constructions and the "si passivante" construction can be used to explain to someone how to do something without giving the impression of having a direct/personal relation with the hearer (spoken case) or with the reader (written case).
In English language I have observed that the impersonal construction is made using "one", "you" or "we".
So, let us consider the following example:
Italian version: "Prima si taglia la cipolla e si mette nel tegame, poi si aggiungono i pomodori tagliati a pezzetti e si lasciano cuocere per mezzora.
English version: First, 'you'/'we'/'one' cut(s) the onion, 'you'/'we'/'one' put(s) it in the pan, then 'you'/'we'/'one' add(s) the tomatoes cut into small pieces, and 'you'/'we'/'one' leave(s) them to cook for half an hour.
Assuming that 'you' is 1 case, 'we' is 2 case and 'one' is 3 case, which is between the three the most impersonal construction in cases like these? Cases in which, I repeat, there is no reason to refer to any singular person in particular.