The Shulchan Aruch 177:2 rules that one who removes the bread from the table must make a new beracha on whatever he eats for the rest of the meal:
ודברים הבאים לאחר סעודה קודם ברכת המזון שהיה מנהג בימות חכמי הגמרא שבסוף הסעודה היו מושכים ידיהם מן הפת ומסירים אותו וקובעים עצמם לאכול פירות ולשתות כל מה שמביאים אז לפניהם בין דברים הבאים מחמת הסעודה בין דברים הבאים שלא מחמת הסעודה טעונים ברכה בין לפניהם ובין לאחריהם דהמוציא וברכת המזון אין פוטרתן אלא מה שנאכל תוך עיקר הסעודה ודין זה האחרון אינו מצוי בינינו לפי שאין אנו רגילין למשוך ידינו מן הפת עד ברכת המזון:
Things that come after the meal before Birchas HaMazon - it was the practice in the times of the Sages of the Gemara that at the end of the meal they would withdraw their hands from the bread, and would remove it, and they would set themselves to eat fruits and to drink - everything that they bring out then, both things that are brought because of the meal and things that are brought not because of the meal, need a beracha both before and after them, because the HaMotzi and Birchas HaMazon only exempt what is eaten during the main meal. This last halacha is not common by us, since we are not accustomed to withdraw our hands from the bread until Birchas HaMazon.
Why is this considered a case that never happens (other that Erev Pesach)? At wedding meals, for example, they usually serve bread at the beginning of the meal, and for the second course there is no bread to be found. Or one who doesn't have a lot of challa, when the bread is finished he continues his meal. And dessert often is served after the table is cleared. Is this just a change in the practice from hundreds of years ago, and we really should apply this halacha, or is there some reason why it doesn't apply to theses cases.