Myth and History
What was the forbidden fruit in the Garden of Eden?
Not produce from a tree. In the Urantia Book the warning was against combining good and evil, compromising the divine plan with shortcut methods. Eve was persuaded to try exactly that, and the famous fruit is a later image for a real decision that cost the Garden its mission.
In the book's own words
Every time the Garden pair had partaken of the fruit of the tree of life, they had been warned by the archangel custodian to refrain from yielding to the suggestions of Caligastia to combine good and evil. They had been thus admonished: “In the day that you commingle good and evil, you shall surely become as the mortals of the realm; you shall surely die.”
The better next question
Who was Enki in Sumerian mythology?