Smith Of Wootton Major by J. R. R. Tolkien
A short, late work by the master. A novelette, even, rather than a novella.
In a village -- "not very long ago for those with long memories, nor very far away for those with long legs" -- there was a custom of the Cook, and every twenty-four years, that Cook held the Feast of Good Children. He recounts the custom, and how it happened that the Cook's prentice was not allowed to succeed him, but another man brought in, and how they baked the cake one time, and put in it trinkets, including a silver star.
It seemed to vanish, but one boy had swallowed it, and some years later, it fell from his mouth to his hand, and he put it to his forehead. It proved to let him enter into Faerie, where he visited for many years, and it showed in his singing and his smithing. He has a few adventures, but it is mostly the wonders -- and a few things that prove to be more in the bittersweet ending.