Can a healthy person eat matzah ashira on Erev Pesach?
According to the Ashkenazi Minhag we don’t eat matzah Ashira (Egg matzoh) on Pesach and not on erev Pesach from the time that we don’t eat chametz. The Sefardi minhag is not to eat Egg Matza from the tenth hour of the day.
Chag Kasher Vsameach
Rema 462-4 because it is possible that drop of water got into the dough, and if there is even a drop of water mixed into a dough mixed with eggs ets, it can make it chametz instantly. Therefore Ashkenazim stay away from egg matzoh on Pesach, unless the person is sick etc. The opinion of the Shulchan Aruch ( Sefrdi minhag) is to permit eating egg matzoh, ( if one was careful that no water got mixed into the dough) therefore they may eat them on Erev Pesach. However from the tenth hour of the day. (approx. 3 hours before sunset) they may not be eaten, similar to not eating cake, from the tenth hour on erev Pesach. Also see O:CH 471-2, Graz 471-4,6.