Challah and brioche, while similar, are not the same bread at all. The most important difference has to do with the fact that challah is part of Jewish tradition, and is kosher to eat with all meals—so it is not made with dairy, i.e. butter. Brioche, on the other hand, is French, so of course it is made with butter!
Both breads are rich, eggy yeast breads, but brioche is definitely richer. (Butter will do that). Challah, by the way, is often a braided loaf. Both make excellent French toast and bread pudding.
Recipe: Challah
