Exodus 29:22

‘Do not eat any of it raw or boiled at all with water, but rather roasted with fire, both its head and its legs along with its entrails.

This is the law of the burnt offering, the grain offering and the sin offering and the guilt offering and the ordination offering and the sacrifice of peace offerings,

“Then the priest shall take the one male lamb and bring it near for a guilt offering, with the log of oil, and wave them as a wave offering before Yahweh.

Then the cook took up the leg with what was on it and set it before Saul. And Samuel said, “Here is what has been reserved! Set it before you and eat, because it has been kept for you until the appointed time, since I said I have invited the people.” So Saul ate with Samuel that day.