The Sages taught that when flour and water are mixed, the dough becomes Hametz after eighteen minutes if it is not baked. Therefore, Masa bakeries prepare their Masot for Pesah in seventeen-minute shifts. They ensure that only seventeen minutes pass from the moment the water is poured onto the flour until the baking is completed. After seventeen minutes pass, they discard the remaining dough, pour water over a new batch of flour, and begin the process again.
This applies, however, only to flour and water. When flour is mixed with fruit juice, the Sages teach, the mixture can never become Hametz. However, there is a disadvantage to using fruit juice for Masa, namely, that if even a single drop of water enters the mixture, the mixture becomes Hametz immediately. Thus, while using fruit juice – such as apple juice – is advantageous in that the dough can never become Hametz, it comes with the risk that a single drop of water can render the batter Hametz immediately.
Due to this risk, the custom among Ashkenazim is to generally forbid eating "egg Masa" – Masa prepared with fruit juice instead of water – during Pesah. Since it can become Hametz through a single drop of water, they avoid using egg Masa on Pesah. They make an exception for ill patients or elderly people who have difficulty eating ordinary Masa. As a general rule, however, Ashkenazim do not eat egg Masa during Pesah.
Sepharadim, by contrast, follow the view of Maran who permits eating egg Masa on Pesah, and not only for the sick and elderly. Of course, one must ensure to use only egg Masa with reliable kosher certification. As we have seen, egg Masa can very easily become Hametz, and it is therefore critical to purchase egg Masa that was prepared under strict supervision by a capable and reliable agency. Furthermore, there is a general rule regarding Pesah that it is always worthwhile to be stringent. The prohibition of Hametz is treated with particular stringency – as it is punishable by Karet (eternal excision from the Jewish people) – and it is thus generally deemed preferable to act stringently. Therefore, even though on the level of Halacha it is certainly permissible to eat egg Masa on Pesah, on the level of Humra (additional stringency), it is preferable to avoid egg Masa on Pesah.
It should also be noted that this discussion does not apply to Masa eaten for the Misva at the Seder on the first two nights of Pesah. The Misva of eating Masa at the Seder requires using "Lehem Oni" ("poor man’s bread"), which is defined as "Masa Shemura" baked with water. Therefore, although one may eat egg Masa during Pesah, on the first two nights of Pesah one must use specifically "Masa Shemura," and not egg Masa.
Summary: It is permissible for Sepharadim to eat egg Masa (Masa baked with fruit juice, instead of water) on Pesah, provided that it was baked under reliable and competent kosher supervision. Egg Masa may not be used for the Misva of Masa at the Seder on the first two nights of Pesah. Furthermore, it is worthwhile to be stringent and avoid eating egg Masa on Pesah, though strictly speaking it is permissible.