Pesahim 22a and Pesahim 22b, starting a list of cases where the Torah allows benefit from an item it prohibited using the verb of אכילה, eating, which R. Avahu said included benefit. Cases discussed: gid ha-nasheh, the sciatic nerve, blood, an ox that is stoned for goring someone to death. For that last one, we also get into the use of et in the Torah, whether it always comes to add something.
