Leviticus 7:3-5

7:3 Then the one making the offering must present all its fat: the fatty tail, the fat covering the entrails, 7:4 the two kidneys and the fat on their sinews, and the protruding lobe on the liver (which he must remove along with the kidneys). 7:5 Then the priest must offer them up in smoke on the altar as a gift to the Lord. It is a guilt offering.