Leviticus 3:5, 16

Aaron’s sons shall offer it up in smoke on the altar [placing it] on the burnt offering which is on the wood that is on the fire. It is an offering by fire, a sweet and soothing aroma to the LORD.

The priest shall offer them up in smoke on the altar as food. It is an offering by fire, a sweet and soothing aroma; all the fat is the LORD’S.