Headed home from a long day at work, suddenly you detect a delicious scent, one you follow to the subway entrance, where you find a vendor selling what looks like a bread roll stuffed with shredded meat and veggies. You're so hungry you order one – okay, two – and chow down, happy to have something resembling a sandwich.But what exactly did you just scarf? Probably donkey meat. Yes, you read that right: you've been eating ass sandwiches.The buns are freshly baked, bready pastries, coated in crispy sesame seeds on the outside, steaming hot and soft on the inside. Stuffed with braised, shredded donkey meat, fresh coriander and sometimes green peppers, this delicious (if salty) street snack, lü rou huoshao, sells for anywhere from 3 to 6 yuan.Supposedly originating from Hebei Province, the eating of donkey meat has a 300-year history; methods of cooking and parts involved vary as greatly as the origin myths. One legend states that during the Ming Dynasty, Prince Zhu Di rebelled against the emperor, his nephew. He lost his first war and was so short of food that his soldiers started to serve him horsemeat-stuffed bread rolls. Later, when he became the third emperor of the Ming Dynasty, the popularity of these bread rolls spread. However, horses were still valuable, so donkeys were used instead.