Matzah with Mayonnaise for the Mitzvah of Matzah

For many people, it is much easier to eat matzah with a spread that adds flavor, such as mayonnaise and the like. The question is whether there is a concern in eating the kazayit of matzah in this manner, especially with the afikoman, which is a rabbinic commandment, [and then the eating becomes even more difficult]. Here is what the Mishnah Berurah (Siman 461, Se'if Katan 18) says: 'If it is permitted to soak it in other liquids and fruit juices or in soup, there are differing opinions among the poskim. Some say it is forbidden because they spoil the taste of the matzah, imparting their own taste to it, while others say that only through cooking does the taste of matzah get spoiled, not through soaking. Therefore, an elderly or sick person who cannot eat matzah soaked in water is allowed to soak it in wine or other liquids, but everyone else who ate matzah soaked in other liquids besides water has not fulfilled their obligation and must eat another matzah, both for the kazayit of the blessing on matzah and for the kazayit of the afikoman. And all this is only when the matzah is soaked in them, but to dip it in them, Rabbeinu Manoach wrote simply that it is permitted, as in this case, the taste of matzah is not nullified.' At first glance, from his words at the end, it is clear that dipping the matzah in them poses no concern, and it seems there is no reason to differentiate between dipping in wine and other liquids and spreading a small amount on the matzah itself. Expansion of the topic: I searched a bit and, at first glance, found almost no discussion on this, [in Dirshu and Piskei Teshuvot this is not discussed at all, and in the book Shaar HaMo'adim chapter 21, it is extensively discussed regarding the mitzvah of matzah during the seven days, where there are many reasons to be lenient to eat with a condiment, especially when it is a small amount, and it brings from the Haggadah of the Gaon Rabbi Yosef Shalom Elyashiv in his name that he inclined to be lenient, however, I found in the book Halachot Chag BeChag by the Gaon Rabbi Moshe Mordechai Karp chapter 16, section 7, that he elaborated a bit on this, and linked it to the disputes of the Rishonim, and one can debate his words as will be explained later, and in any case, he also simply holds that according to the Mishnah Berurah, one can be lenient in this]. Here, it seems that the only one I saw who discusses this and raises a concern is the Gaon Rabbi Moshe Mordechai Karp, but it seems that from his words, the permission in this is clear and broad, because while the Mishnah Berurah only brought the words of Rabbeinu Manoach, he brought three more Rishonim who explicitly permitted, but on the other hand, he brought two sources for prohibition, therefore he wrote that one should not be lenient except for the sick and elderly, but it seems that the two sources for prohibition are not clear at all, and the Rishonim who permit are clearly expressed in their words and they are many, and I will explain a bit. Here, in several Rishonim, it is explicitly stated that there is no concern to dip the matzah in something that has taste, and they are: Rabbeinu Manoach [as brought in the Mishnah Berurah], the Raavad [chapter 6 of Chotzaat Maaser, according to the Tosefta that one fulfills the obligation with seasoned matzah and explained that it was seasoned after baking], and so it is in the Ran and Meiri [Pesachim 115], to resolve the question of Tosafot why the charoset does not nullify the maror, since it is the way of dipping [all this was brought by the Gaon Rabbi Moshe Mordechai Karp there]. And it seems from the words of Tosafot, who questioned the charoset of the maror that it nullifies its taste even though it is the way of dipping, it proves, it seems, that their opinion is to forbid even in the way of dipping, but this is not so because it can be said that the opinion of Tosafot is that the charoset is not just dipping but one eats a lot of it, and it is necessary because the opinion of Tosafot is that in a small amount there is no nullification of taste as Tosafot wrote there to explain why one fulfills the obligation with seasoned matzah, and therefore they hold that the charoset is not just dipping, and so it is written in Torat Chesed Siman 49, Se'if Katan 9 [this too from the words of the Gaon Rabbi Moshe Mordechai Karp there]. But the Gaon Rabbi Moshe Mordechai Karp concludes there that it depends on the opinions if one dips the matzah in charoset, that the opinion of the Rambam is that one dips the matzah in charoset, and Rabbeinu Manoach and the Tur in the name of the Manhig objected that the charoset nullifies the taste of the matzah, and Rabbeinu Manoach answered that it is the way of dipping and does not nullify, [and so answered the Radbaz], and consequently, since the custom is not to dip the matzah in charoset, it means we hold initially to be concerned for those who hold that there is nullification of taste even in the way of dipping [and seasoned matzah discussed is seasoned before baking so that all is part of the matzah], this is the essence there, and based on this he concludes that one should not be lenient initially, but it seems this is not understood at all, this claim, from where does it come that the reason not to dip matzah in charoset is "due to concern", because it can be said simply that it is because we hold that "there is no need" to dip the matzah in charoset, because the whole reason is for softening and this is not in matzah [and on the contrary, the opinion of the Rambam in this requires explanation and this is not the place for it], but there is no hint of evidence that they were stringent in dipping initially, and so it seems from the words of the Mishnah Berurah who simply stated the words of Rabbeinu Manoach that it is permitted to dip and did not mention any side to be stringent initially and yet wrote that one does not dip the matzah in charoset. From all this, it emerges that in four Rishonim it is explicitly stated to permit, Rabbeinu Manoach, Raavad, Ran, and Meiri, and from Tosafot there was room to learn prohibition but it is necessary that they are not speaking of small dipping, and we are left with no source except from the fact that one does not dip the matzah in charoset, and it seems there is no hint of evidence in this. However, it seems that the custom is not to be lenient in this, and it should be examined if there is indeed a reason to be stringent. I would be happy to hear opinions.

Hello,

One should not eat the kazayit of matzah with a spread.

As it is stated in the Gemara (Pesachim 115a) that one should not eat matzah and maror together, as the taste of the maror nullifies the taste of the matzah.

Even salt, the Ashkenazim have the custom not to dip in the matzah of the mitzvah, as explained in the Rema (Siman 475, Se'if 1).

However, if one ate in such a manner, it should be discussed whether they have fulfilled their obligation. See sources.

From the Gemara Pesachim 115a, it implies that one does not fulfill the obligation.

However, from the words of Tosafot (Zevachim 78a and Menachot 23a), it is clear that only with maror it is said that its bitterness nullifies the taste of matzah, but with other things, the taste is considered primary, and one fulfills the obligation of matzah. Tosafot also wrote in Pesachim (115) that even with seasoned matzah, one fulfills the obligation. 

Shulchan Aruch (Siman 475, Se'if 1) and they dip them in salt. Rema: and the custom is not to dip them in salt on the first night,