Leviticus 7:10-12

10Grain that is dry is also a gift. And grain that a man mixes with oil is also a gift. They should give them to Aaron's sons.

11These rules are for friendship offerings to the Lord.

12If a man wants to thank God, he must give an animal and flat loaves of bread. He must mix the flour for the bread with oil. He must not mix the flour with yeast.