It is forbidden to eat Masa on Ereb Pesah (14 Nissan). The primary reason for this prohibition is that one should eat Masa on the night of Pesah with a hearty appetite.
If one mistakenly ate Masa on Ereb Pesah, he recites Birkat Ha’mazon after eating. Even though a person who ate non-kosher food does not recite a Beracha Aharona or Birkat Ha’mazon after eating, one who eats Masa on Ereb Pesah recites Birkat Ha’mazon. This is the ruling of Hacham Ovadia Yosef, in Hazon Ovadia – Pesah (p. 196). He explains that unlike non-kosher food, which is intrinsically forbidden, Masa on Ereb Pesah is intrinsically permissible, and it is only due to the time-period that eating it is prohibited. Therefore, it requires Birkat Ha’mazon despite the prohibition that was mistakenly violated.
It is permissible to eat egg Masa on Ereb Pesah, because it cannot be used to fulfill the Misva of Masa at the Seder. However, products made from Masa meal, such as Masa meal cakes, may not be eaten on Ereb Pesah. Even though these cakes contain sugar, honey and other ingredients, and are obviously not plain Masa, they nevertheless may not be eaten on Ereb Pesah. Masa meal products differ from egg Masa, which is kneaded with fruit juice instead of water and is thus not considered Masa. Masa meal, however, is actual Masa that was ground into flour. This flour may not be eaten on Ereb Pesah, even after it has been mixed with other ingredients and baked.
It goes without saying the products made from potato flour may be eaten on Ereb Pesah. Potato flour cakes, for example, do not contain any Masa meal, and in fact the Beracha over such foods is "She’hakol," and they are certainly permissible on Ereb Pesah.
May one feed Masa to children on Ereb Pesah?
Hacham Ovadia (Yalkut Yosef – Pesah, p. 238) writes that children who are old enough to understand the story of the Exodus, and regarding whom the Misva of telling the story of the Exodus ("Ve’higadeta Le’bincha") applies, should not be fed Masa on Ereb Pesah. However, a very young child, who is not yet old enough to understand the concepts of Pesah, such as a two- or three-year-old child, may be fed Masa on Ereb Pesah. A child’s status in this regard depends on his or her level of maturity and understanding.
Is it permissible to eat Marror on Ereb Pesah? For example, if a person is eating a salad, and he wants to include Romaine lettuce – which is what Sepharadim use for Marror – is this permissible?
Hacham Ovadia Yosef records a custom to refrain from eating Marror on Ereb Pesah, but adds that this is not the accepted practice, and it is thus permissible to eat Marror on Ereb Pesah. He also records a custom not to eat eggs on Ereb Pesah, since eggs are eaten at the Seder in commemoration of the Hagiga sacrifice that was offered on Ereb Pesah during the times of the Temple. However, Hacham Ovadia notes that there is no source for this custom, and it is therefore entirely permissible to eat eggs on Ereb Pesah. The Sages already forbade eating Masa on Ereb Pesah, and there is no reason to add new customs forbidding even more foods on this day.
Summary: One who mistakenly eats Masa on Ereb Pesah nevertheless recites Birkat Ha’mazon. Egg Masa may be eaten on Ereb Pesah, but Masa meal products are forbidden. Children who are old enough to understand the story of the Exodus should not be fed Masa on Ereb Pesah, but young children who have yet to reach that stage may be given Masa. It is permissible to eat Marror and eggs on Ereb Pesah.
