2018’s Free Chocolate is an interstellar adventure by Amber Royer.
Humans were surprised and alarmed to discover that alien Krom had infiltrated the Earth, passing themselves off as Homo sapiens. Humans were surprised and enraged to discover that their Krom visitors had used their time on Earth to purchase samples of particularly enticing Terrestrial products: coffee, sugar, tea, vanilla.
By the time technologically backward Earth had adjusted to the new state of affairs and was finally able to market their unique biological materials to the galaxy … earthlings found that the Krom already controlled the market for the sampled goods. In doing so, the Krom had violated no galactic regulations. Just business. Nothing to see here. Humanity could only react with impotent fury and close off Earth to other aliens.
But the Krom overlooked one potential export: