Why must eat apple on the Christmas Even~???

I did some research. There is a lady named Ruth Sawyer that tells a german story of The Christmas Apple. Basically, it's about a small town who goes to the cathedral every Christams Eve to present their best gift to the statue of the Virgin Mary and baby Jesus. A clockmaker named Hermann usually has no money left for a gift because he spends his spare time and money helping children, repairing their toys, and helping those in need. But one year he makes a beautiful clock for Christmas Eve and everyone in town knows it. He has to stop taking in work to finish it in time, and his cupboards are bare. He buys an apple figuring it will be his supper for two nights. But just then a lady comes to his door crying; her husband has gone to hospital and the children have nothing to eat. Hermann takes a clock and tries to sell it, but nobody wants to buy. Finally the rich man in town affers $1000 for his Christams clock. Hermann has no other way to get money for the young woman, so he sells the Christmas clock - but only for $100, which he then gives to the family in need. The apple is all he has left, so he takes it and gives it as his Christmas present to the statue. The townspeople are awed, because they witness a miracle: the baby Jesus reaches down from Mary's arms to take the apple for his gift. I don't know if there are other stories, this is the only one I found.