QUESTION: Why do we bake our matzot round?

ANSWER: It was Pesach when the three angels visited Avraham (see Rosh Hashanah 11a, Tosafot). After they accepted his invitation to eat with him, he told Sarah to quickly get flour and “lushi va’asi ugot” — “kneed and make cakes” (Bereishit 18:6). In Hebrew the word “ugah” means a circle (see Ta’anit 23a, Rashi). Since Avraham baked round matzot on Pesach, we follow suit.

QUESTION: What is the significance of round matzah?

ANSWER: In the olden days paganism was prevalent. It was common practice for one to worship more than one deity or idol, and the people would indicate through the bread they baked how many gods they had. If, for instance, one had two gods, he made his bread with two points, and if one had five gods, his bread was shaped to have five corners. In order to accentuate our belief in one G‑d, it was Avraham’s practice, and also the practice of our fathers in Egypt, to make round bread, indicating that we believe in only one G‑d and that He has no beginning or end.

(שו"ת יהודה יעלה - מהר"י אסאד - או"ח סי' קנ"ז)