Theign Yie Phan has to stop herself from chowing down a banh mi every day of the week. But it’s hard to resist when you’re the head chef of a restaurant that specialises in the delicious Vietnamese sandwiches. “It is a good between-service snack. I eat one every other day. It is definitely not something you get sick of,” she says with a laugh, as she stands in front of an array of colourful ingredients ready to be stuffed into a crusty baguette at Le Petit Saigon in Wan Chai. Along with pho, the noodle soup, banh mi is one of Vietnam’s most famous culinary exports – a French-style bread filled with rich meats and zingy, fresh vegetables and herbs.