Rabbi Adler wrote: "Ground Matza (Matza meal) could actually be used in extenuating circumstances as bonafide Matza for the purpose of the Mitzvah." Can you please elaborate on such circumstances (with mekoros)? Thanks.

Shalom, Thank you for your question. The Mishna Brurah (on the Shulchan Aruch, Orech Haim, 471, 18) writes that someone who eats matzah has been crumbled into small pieces clearly fulfills their mitzvah of eating matzah on Seder night. The reason why Rabbi Adler wrote that this law is only in “extenuating circumstances” is because one should ideally have three pieces of matzah on the seder plate, and say the blessings over two whole pieces with the broken half piece in the middle – and not over ground matzah. But, if one did not have whole pieces of matzah, and only ground matzah, that would be eligible to use to fulfill the mitzavh of eating matzah on Seder night. Of course, this only applies if the matzah meal has not been boiled, recooked, or mixed with other things. Even if it has just been soaked with water the law is not so simple – see the Shulchan Aruch 461,4 for the details. Blessings.