Teacup

Sand becomes glass, glass becomes bottles, bottles become water, and the teapot does the rest. Nothing in the chain is gated behind a drop, a season or a boss besides Skeletron, whose dungeon supplies the bones for the pot. That makes this the fallback for a character who has run out of everything else, and one of the few foods you can produce in unlimited quantity without leaving the base.

It grants the weakest of the food buffs and it expires quickly, so you will be eating them constantly. Use them to stay topped off between jobs and save a proper drop food for the boss. Carrying a stack costs nothing, which is really the point.