There is a custom to dip the Halla in either sugar or honey at the beginning of the Rosh Hashanah meals. The Kaf Ha’haim (Rav Yaakov Haim Sofer, Baghdad-Israel, 1870-1939) writes that the sugar or honey does not serve as a substitute for salt. The requirement to dip bread in salt anytime a person eats bread applies on Rosh Hashanah no less than on any other day of the year. Therefore, on Rosh Hashanah, after one recites the Beracha of "Hamosi," he should dip the Halla in salt three times, as usual, and then add a bit of sugar or honey. The addition of sugar or honey does not obviate the need for salt.
There is another custom that some people observe to use specifically round Hallot on Rosh Hashanah, as opposed to the normal oval-shaped, braded loaves. The Hatam Sofer (Rabbi Moshe Sofer of Pressburg, 1762-1839) explained this custom as an expression of our hopes and prayers that we will receive boundless blessings during the coming year. Circles are unique in that they have no beginning or end. We therefore use round loaves of bread on Rosh Hashanah as a symbol of our hopes that God will bestow unending blessings upon us and the entire Jewish nation during the coming year.