Lembas

Gimli's first guess was cram, of the sort the Dale-men bake for the road. So it is, the Elves answered — but they call it lembas or waybread, and it puts more strength into a traveller than anything Men bake, besides being, by every account, the pleasanter of the two. A crisp corner was enough to make Gimli eat the whole cake with relish, and a single cake would carry a walker through a full day on the road. Its worth showed where nothing else would have served: on the road to the Mountain it grew more potent the longer they leaned on it alone, untouched by other fare. It did not satisfy desire — Sam's mind filled with the memory of simple bread and meats — what it sustained was the will: it carried a traveller further, and held body and limb to the task past anything mortals manage unaided.