Question:

What are some laws of Lechem Mishneh?

Discussion:

The reason why we use two loaves of bread is to remind us of the double portion on the Mann that came down on Friday. This is also the reason why there is a custom to cover the challah on top and on bottom since the Mann came sandwiched between two layers of dew.

Men and women are equally obligated in using Lechem Mishneh at each of the three meals on Shabbos (M.B. 274:1).

Even if the bread has a crack, it is considered complete as long as the bread will not break if it is picked up by the weaker section (M.B. 167:11). If two loaves became attached during the backing process they may be separated from each other and would still be considered complete (Machtzis Hashekel 274:1).

As long as the loaf is not missing more then 1/48^th of the entire loaf it is considered complete (Machtzis Hashekel 274:1). However, there are others that say it is no longer considered whole (Aruch Hashulchan 274:5)

If one does not have two complete loaves of bread, he should use one loaf and one piece of bread. If one has no complete loaves then he should make Hamotzie on two pieces of bread (Minchas Yaakov 12). If one has a whole loaf and a whole cake he may use the cake as part of the Lechem Mishneh. In this case he should eat from both the loaf and the cake (Shu”t Daas Moshe 4).