In the olden days, the meal was served in two stages. First, they would eat the main course with bread; afterwards, the table with the bread was removed, and a new table with desert was brought. Maran, in Siman 177, rules that this "Siluk Hashulhan"-removal of the table- constitutes a "meal within a meal." Therefore, not only must new Berachot be recited before eating the desert, but also after the dessert as well. That is, after the desert, a Beracha Aharona is recited on the dessert and then Birkat Hamazon is recited on the main meal. However, Maran continues, nowadays that we do not bring a new table for dessert, it is considered one long meal. Therefore, a Beracha is made before dessert, but the Birkat Hamazon at the end covers the dessert, and no separate Beracha Aharona is necessary.
The Nahar Misrayim (R. Rephael Aharon Ben Shimon, Egypt, 1848-1928) writes a Chidush that the Halacha of "Siluk Hashulhan" can also apply nowadays. While removing the table is not the standard practice, nevertheless, people sometimes do remove the tablecloth before dessert. This also constitutes "Siluk Hashulhan," and the dessert would require a separate Beracha Aharona before Birkat Hamazon. The Hesed L’Alaphim (R. Eliezer Papo, 1725-1826) adds that placing bread on the table, after removing the tablecloth, does not help. The act of removing the tablecloth indicates a person’s "Da’at"-intent to end the previous stage of the meal.
In light of these opinions, one must be careful in such a situation, as he may be required to make a separate Beracha Aharona. This issue could be the explanation for an interesting Halacha brought by the Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), which many Poskim have tried to explain. The Ben Ish Hai states that one should eat a little bread right before Birkat Hamazon. Perhaps, this practice is meant to alleviate this problem. Eating bread at the end of the meal demonstrates that even if the tablecloth was removed, the meal is one uninterrupted entity. Hacham Ovadia rules that if one does not follow this custom of the Ben Ish Hai, he must make a separate Beracha Aharona on the desert, if the tablecloth was removed.
SUMMARY
If one removed the tablecloth at the end of a meal and then served desert, a separate Beracha Aharona must be recited on the desert before the Birkat Hamazon.
