One of the enduring conversations among Viet cooks focuses on this topic: How do you fry cha gio well? If you’re unfamiliar with these delicious rolls, they are a super popular that you’d find at parties, restaurants, nosh sessions. They are a good time, celebration food. They’re often filled with a sparkly mixture of bean thread (cellophane) noodles and seafood and pork, and there are vegetarian options too.
Cha gio originated in Saigon, and their old school name is cha gio Sai Gon. Nowadays in Vietnam, the rolls also go by nem ran, a term favored in Hanoi. Adding to the name confusion is the fact that in English, some Viet-Americans call them “Vietnamese eggrolls” though they are not made with Cantonese eggroll skins. Imperial roll, a translation of pâté impérial (their moniker in French) is more neutral and speaks to their luxurious-seeming flavor despite being made from humble ingredients. Use the term that you're comfortable. For me, I stick with the original cha gio (“chah yaw” or “chah zaw” for southern and northern pronunciation, respectively).
Back to the initial question. Professional and home cooks alike have many tricks and theories on how to keep cha gio from busting open, achieving a handsome color, and creating a crisp, slightly chewy texture. There are Viet cooks who’ll say that the trick to making crisp cha gio is to use wheat-based lumpia or Chinese spring roll skins (banh trang Tau). Break away from the traditional banh trang rice paper altogether, they advocate. In Vietnam, there’s also a net-like wrapper called banh trang re, which fries up lacy, crispy, albeit kinda greasy.