What do the gods give to Utnapishtim and his wife as recompense for their tribulations?

A forerunner of Noah in the Bible, Utnapishtim is instructed by the god Ea to build a boat to protect him from the great flood that he and the other gods are about to unleash upon the world. In return, he will be granted immortality, one of the most important themes of The Epic of Gilgamesh. The flood causes enormous devastation, wiping out the whole of humanity. But Utnapishtim and his wife survive and are rewarded for their obedience to the divine will by being made immortal.
Gilgamesh seeks immortality for himself, and Utnapishtim subjects him to the demanding test of staying awake for six days and seven nights. But Gilgamesh is unable to do so, falling asleep after an ocean mist descends. Having flunked the immortality test, the king must return home to Uruk and never come back to the Faraway. But before he goes, Utnapishtim's wife implores her husband to give Gilgamesh a parting gift. Utnapishtim tells Gilgamesh of a magical plant called How-the-Old-Man-Once-Again-Becomes-a-Young-Man, which is to be found at the bottom of the sea and which will restore the king's youth. Gilgamesh descends to the very depths of the water, where he successfully locates the plant. He promises to take it back with him to Uruk, where he will use the plant's magic properties to rejuvenate the city's elders.