You can’t make a legitimate vermicelli bowl without Nuoc Mam Cham, also known as Vietnamese Fish Sauce Dipping Sauce.  This is a simple “shake and make” recipe, which will keep about a week in the refrigerator.  As the name suggests, it’s also a great dipping sauce for Vietnamese egg rolls.  Look for Three Crabs Fish Sauce, which is available in most grocery stores — it’s a favorite among Vietnamese cooks.