The Talmud exegetically understands that when the Torah refers to Matzoh as Lechem Oni, this means "bread upon which many things are answered." Rashi explains that this means that one must recite the Haggadah and complete the Hallel while the Matzoh is present. This is difficult to understand because by the time one is finishing the Hallel at the Passover Seder one has already eaten the Afikomen and has therefore eaten the Matzoh, so there is no more Matzoh present on the table at the time of the completion of the Hallel. Rabbi Shlomo Kluger (1783-1869) explains that really the Talmud's requirement is not to have Matzoh present at the time of the conclusion of the Hallel, but rather the requirement is that one should have the taste of Matzoh still in one's mouth at such time. He explains that this is why the Mishnah says that one is not allowed to eat dessert after eating the Paschal sacrifice, and the Talmud explained even after the eating of the final Matzoh one is not allowed to eat a dessert. The reason for the prohibition of eating a dessert after Matzoh, according to Rabbi Shlomo Kluger, is in order that one should retain the flavor of Matzoh in his mouth while reciting the Hallel. Rabbi Eli Chaim Swerdloff (Rosh Yeshiva of Paterson) explains, based on the words of Rabbi Tzidkiyah ben Avraham HaRofey Anaw (1230-1300), that Hallel on the night of Passover is said as praise to HaShem for the ritual foods. This echoes the words of Rabbi Yehuda Low (1525-1609) who explained that Hallel on the Seder night is split into two parts so that first part should be considered part of the eating of the Matzoh, and the second part should be considered part of the eating of the Paschal lamb. Accordingly, both the eating of the Matzoh and eating of the Korban Pesach themselves require the recitation of the Hallel. Therefore, even if the Matzoh is not physically present by the time one is finished saying the Hallel, the singing of the Hallel is still considered part of the eating inasmuch as one has fulfilled his halachik requirement of singing with the eating of the Matzoh.