I just posted about Pho: The Dish, so now some detail on the dipping sauce. The dipping sauce can be served on the side or mixed directly into the bouillon. We combine four components: hot Sriracha chili sauce, Hoisin sauce, pickled red shishito pepper paste, and lime juice. This is a rare occasion where we use finished products rather than trying to make them ourselves from scratch.
The shishitos are split to remove the seeds, then pickled in a mixture of white rice vinegar, water, sugar and salt. After few day they are mixed with some of the pickling liquid into a paste. The Sriracha is composed of red chili, vinegar, garlic, sugar and salt. The Hoisin sauce is composed of potato starch, sugar, soy bean, vinegar and salt.