When was the first time someone wrote down how to make food or drink in something we'd recognize as a recipe?
On a related note, what is the earliest known cookbook?
There may be older fragmentary documents, but the oldest cookbook I'm aware of is Akkadian and dates to around 1800 BC: http://www.library.yale.edu/neareast/exhibitions/cuisine.html
Before that time things get a little more fuzzy. We know the ancient Egyptians used oils, salt, and spices since they have words for them (tpnn for cumin, saw for coriander, hmd for vinegar, to list a few) ...the difficulty is, as with much of their philosophy, construction techniques and medicine, they didn't bother to write any of their recipes down on anything permanent enough to last to the modern day. We can make a few guesses from scenes of food preparation, though, as well as from recovered cookware.