Q. One who is in the middle of a Purim seuda and (unexpectedly) receives mishloach manos during his seuda, does he need to make a bracha on the food that he received? Does it make a difference if he was expecting it, or not?
A. Horav Shlomo Miller’s Shlit’a opinion is that if the newly arrived food was unexpected, one should recite a brocho on it, as it was not included in the blessings already said, even if it was an hamotzi brocho. However, if it was expected, it was already included by the corresponding blessings recited.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a