Cooking Parve and Basar Be'halab
Regarding the position of Shulhan Arukh (Maran. Rabbi Yosef Karo) on cooking parve items in a clean (kosher) meat pot that is ben yomo (used within the last 24 hours) with the intention to eat the parve items together with dairy (or vice versa), Shulhan Arukh states (Yore Deah 95:1): "Fish cooked in a clean meat pot are allowed to be eaten with dairy."
Some interpret this as only when the parve was already cooked in the meat pot is it permissible in the first instance to eat it with dairy but not to cook it so intentionally.
However, it's probable Shulhan Arukh had nothing against cooking parve with intention to eat with the opposite number of the pot. The formulation "Fish cooked" may not mean only bediabad (if it happened) - he may have so written it to flow with the continuation of the halakha: "but if the pot wasn't washed well and what was stuck to its surface is more than 1/60 of the fish, it is prohibited to eat them with dairy." The Gemara often gives this type of interpretation about a Mishnah.
More important is that in his Bedek Habayit, Maran explicitly states that it is permitted in the first instance to cook parve in a clean meat pot to eat with dairy. This is published in all present-day standard editions of the Bet Yosef at the end of the siman.
Some say that Maran may have changed his mind in the few years between his writing Bedek Habayit and Shulhan Arukh. But considering that he explicitly stated the permissible position and that Shulhan Arukh is not clearly and necessarily a reversal, it is more probable he did not reverse himself.