Leviticus 2:11 "For you shall burn no leaven, nor any honey, in any offering"
Besides animal sacrifices, meal offerings are also presented on the altar.
These offerings are made of wheat and oil, and they are called a "Minchah Offering".
The ingredients of the Minchah are mixed and formed into a dough.
This dough may not be leavened dough, which means it must not rise high like bread. (Just like on Pesach when we are forbidden any leavened dough, which is called Chametz.)
Also, a sweetener like honey, fruit juice or date extract may not be used, because it causes the dough to rise. We are forbidden to present dough that has risen as a meal offering upon the altar.