Bao – steamed or fried buns – are a staple of Chinese cuisine. The pockets of dough can be filled with various types of meat and vegetables. Traditional stuffings include pork, shrimp and scallions, but operators are also experimenting with fried fish and cabbage slaw. Bao are only found on 1 percent of U.S. restaurant menus, but they’ve seen 54-percent growth over the past four years.