Having said "Sh'nei ha'Omer la'Echad", why does the Torah insert "Liktu Lechem Mishneh"?
Rashi: It means that its taste was special too.
Da'as Zekeinim: We learn from "Sh'nei ha'Omer la'Echad", that the portion of Manna doubled on Shabbos, so that they ate two loaves of bread for each meal, instead of the usual one.
Shabbos, 117b: To teach us the obligation to eat two loaves (at each meal) on Shabbos, or, as the Gemara concludes, to recite the B'rachah over two loaves. 1
Shabbos, Ibid.: Since the Torah writes "Liktu" Lechem MIshneh" and not 'Ichlu'. See Torah Temimah, note 30, who elaborates.
Why were people surprised when on Friday, they found that they had collected two Omers per person, seeing as Hashem had already informed them (in Pasuk 5) that this would occur?