Translation:Shulchan Aruch/Yoreh Deah/328

Seif 1: At the time when one separates out hallah he should bless, “אשר קדשנו במצותיו וצונו להפריש "תרומה “who has sanctified us with Mitzvot and commanded us to separate the priestly gift.” (or to separate hallah להפריש חלה). Therefore, it is forbidden to separate his hallah naked since it would be impossible for him to make a blessing while he is naked, but a woman is permitted so long as her genitalia [lit. “lower face”] are concealed in the ground. (and in a case when he is separating 2 hallot, he should only make a blessing when separating from the first)