Answer: In the previous Halacha we have explained the primary reason for answering “Baruch Hu U’Varuch Shemo” after hearing Hashem’s name, for this was indeed the custom of the Rosh who would answer “Baruch Hu U’Varuch Shemo” every time he heard Hashem’s name being recited within a blessing. We have likewise pointed out that although it is a Mitzvah to answer “Baruch Hu U’Varuch Shemo,” nevertheless, since this is not completely obligatory, one should not answer “Baruch Hu U’Varuch Shemo” during Pesukei De’Zimra and the like. Although regarding answering “Amen” to blessings we follow the ruling that Amen should be answered to blessings one hears while one reciting Pesukei De’Zimra, nevertheless, “Baruch Hu U’Varuch Shemo” is completely different in that it is not completely obligatory; therefore, one may not interrupt one’s Pesukei De’Zimra by answering “Baruch Hu U’Varuch Shemo.”
Answering “Baruch Hu U’Varuch Shemo” to Blessings One Fulfills His Obligation With
Hagaon Rabbeinu Shmuel Abohav writes in his Responsa Devar Shmuel: “I have already pointed out to my peers that the aforementioned custom of the Rosh (answering “Baruch Hu U’Varuch Shemo”) only applies to blessings which one is not obligated to recite. However, when the listener has in mind to fulfill his obligation by hearing the blessing and the one reciting the blessing likewise has in mind to include the listener (such as the blessings of Kiddush, Megillah, and the like through which one fulfills one’s obligation to recite the blessing by merely hearing them), one may not interrupt in the middle of the blessing by reciting ‘Baruch Hu U’Varuch Shemo,” for since one who listens is tantamount to reciting the blessing on his own, by answering ‘Baruch Hu U’Varuch Shemo’ in the middle of the blessing, it is as if one is interrupting in the middle of the actual recitation of the blessing.”
This means that it is quite clear that when one fulfills one’s obligation by merely hearing a blessing, it is as if one has recited the blessing himself. Thus, if one recites “Baruch Hu U’Varuch Shemo” while hearing a blessing, although one has answered “Amen” to that blessing, one has not fulfilled one’s obligation, for it is as if one has recited the blessing and said, “Baruch Ata Hashem Baruch Hu U’Varuch Shemo Elokeinu Melech Ha’Olam etc.” in which case one certainly has not fulfilled one’s obligation. Many great Poskim rule in accordance with the Devar Shmuel.
Nevertheless, there are certain communities which customarily answer “Baruch Hu U’Varuch Shemo” even to blessings which one fulfills his obligation with, such as Kiddush. However, Hagaon Harav David Pardo zt”l writes the following regarding this custom: “I attest to the fact that I have heard from Hagaon Harav Avraham David Papo who heard from his great father who heard from the saintly man of G-d, Rabbeinu Moshe Zakut zt”l exactly like the opinion of our great rabbi, glory of the generation, Moreinu Harav Shmuel Abohav.” This is indeed the consensus of most Poskim who rule that one must not answer “Baruch Hu U’Varuch Shemo” upon hearing the name of Hashem recited in a blessing one fulfills one’s obligation with, such as Kiddush and Havdala.
Thus, halachically speaking, it is indeed a great Mitzvah not to answer “Baruch Hu U’Varuch Shemo” to blessings with which one fulfills one’s obligation. Even if one has customarily recited “Baruch Hu U’Varuch Shemo” to such blessings until this point, it is proper to forsake this specific custom out of concern for the opinions of the Poskim who forbid doing so.
The Moroccan Custom
On the other hand, many Moroccan Jews strictly adhere to this custom, for many communities in Morocco customarily answered “Baruch Hu U’Varuch Shemo” to all blessings. Maran Rabbeinu Ovadia Yosef zt”l did not appreciate this custom at all, for he claimed that this custom did not originate from the rabbis of Morocco, rather, the laymen instituted this custom themselves. Even if this was the opinion of several Moroccan scholars, in such a case where an overwhelming majority of Poskim agree that one must not answer “Baruch Hu U’Varuch Shemo” on such blessings, we must accept their opinion as Halacha and abolish the custom of those who answer “Baruch Hu U’Varuch Shemo” on every single blessing.
However, the great and righteous late Chief Rabbi of Jerusalem, Hagaon Harav Shalom Mesas zt”l, opposed the opinion of Maran zt”l and vehemently upholds this ancient Moroccan custom. When he was alive, both luminaries enjoyed a lengthy dialogue on this topic, but Maran zt”l refuted all of Harav Mesas’s claims on this issue. Nevertheless, Hagaon Harav Mesas did not accept Maran’s opinion on this matter and refused to abolish this age-old Moroccan custom. Several other Moroccan rabbis arose after him supporting this custom with various sources. Thus, this disagreement still continues until this very day. One should not, G-d-forbid, cause strife or conflict regarding such matters which are not exactly from the fundamentals of our religion; there is much more to be lost than gained by fighting about this issue.
Summary: One should not answer “Baruch Hu U’Varuch Shemo” on blessings which one fulfills one’s obligation with, such as Kiddush, Havdala, the blessings on reading the Megillah, and the like.