The Gemara of Pesachim establishes that if dough is kneaded with fruit juice, as opposed to water, it cannot become chametz. Unlike water, fruit juice does not have the ability to cause dough to become leaven as defined by halachah. The Shulchan Aruch accepts the majority position which maintains that fruit juices do not cause dough to become leaven at all. Therefore, one may eat matzah prepared in this manner which is commonly referred to as “Egg Matzah” on Pesach, provided that he is certain that not a single drop of water was mixed into the dough. If water is added to a mixture of dough and fruit juices, the dough becomes chametz immediately. Partaking of Egg Matzah is permissible only if it was prepared under strict supervision, such that it can be ascertained that no water was mixed into the dough.
Ashkenazim follow the ruling of the Rama (a”h) who held that one should satisfy the stringent view of and abstain from Egg Matzah on Pesach. Ashkenazim allow Egg Matzah only for the elderly or ill patients who find it difficult to partake of standard Matzah. It should be noted that Pesach is a time when people follow stringencies that are not required on the strict level of halachah. Accordingly, even a Sepharadi who wishes to follow the stringent view and refrain from eating Egg Matzah on Pesach may certainly do so, and regarding such a person it is said, “Tavo alav berachah – he is deserving of blessing.”