The Mishnah teaches that in order to prepare udder for eating, it must be opened so that the milk can be removed. In theGemara Rav Yehudah teaches that the requirement is for the udder to be cut crosswise and pressed against the wall.
The Gemara follows this by relating the following story about Yalta, Rav Nahman‘s wife:
Yalta once said to Rav Nahman: ‘Observe, for everything that the Divine Law has forbidden us it has permitted us an equivalent:
– it has forbidden us blood but it has permitted us liver;
– it has forbidden us intercourse during menstruation but it has permitted us the blood of purification;
– it has forbidden us the fat of cattle but it has permitted us the fat of wild beasts;
– it has forbidden us swine’s flesh but it has permitted us the brain of the shibbuta;
– it has forbidden us the married woman but it has permitted us the divorcee during the lifetime of her former husband;
– it has forbidden us the brother’s wife but it has permitted us the levirate marriage;
– it has forbidden us the non-Jewess but it has permitted us the beautiful woman taken in war.
I wish to eat flesh in milk, where is its equivalent?’
In order to satisfy her request, Rav Nahman asked the butchers to prepare roasted udders for her. The Gemara asks how he could do so, given the requirement to cut it crosswise and press it against the wall, and explains that that requirement is limited to situations where the udder was to be cooked, but that it does not apply when the udder was roasted.
Rav Nahman’s wife, Yalta, was a member of the family of the Exilarch. From the stories related in the Gemara about her, it is clear that she was a strong-willed woman, who expected to be treated with respect by her husband and by the other Sages. Furthermore, the stories show that she was learned in her own right and that she participated in the discussions that Rav Nahman had with his contemporaries and peers.
One of her examples of something that the Divine Law permitted was the brain of the shibbuta, whose taste was that of pork. Scholars have searched for – and may have found – the shibbuta in Turkey. See this article for details –halachicadventures.com/wp-content/uploads/2009/09/shibuta-JerPost-s.pdf.