Vanilla Extract
The complicated process that needs to happen to grow real vanilla beans means it’s one of the most expensive per-unit foods in your grocery store, and the price-per point of vanilla beans means that extract can be mind-bogglingly expensive.
First, a bit about what’s in imitation vanilla. That’s made from a compound called vanillin, and chemically, it’s the exact equivalent to the stuff that makes real vanilla, well, vanilla. Vanillin is a lot cheaper, though, and that’s because it’s a byproduct that can be extracted from things like coal and wood.