Mushroom

Eat it where you find it. The game text promises a small boost to health, hunger and thirst, nearly the same words it uses for corn, and you need no fire and no planter for it.

Fresh spawns get the most out of it. You wake up on the beach, head inland through the trees with a rock, and every mushroom by a trunk is a little health back without stopping. Over the first few minutes those mouthfuls add up.

That is all it does. No recipe asks for it, you cannot grow it, and it is no match for a real meal. Treat it like blueberries or black raspberries: eaten on the move, then forgotten. For food that actually carries you, look through the rest of the food category.