Parashas Ha-Man

I've gotten a few reminders that today is the day of the year (the Tuesday of the week of the Torah portion Beshalah) to recite Parashas Ha-Man, the Torah passage about the manna, in order receive a segulah (hard to translate) for a livelihood.

Anyone know the source of such a practice? If you answer Reb Mendel of Riminov, I will only ask what his source was.