Here are two staples that I use for making dumplings and Vietnamese food: wheat starch and rice paper. I employ the former for dim sum such as har gow and the latter for hand rolls or fried cha gio imperial rolls. I suffer allergies but not many food-related ones so I've not thought much about cross-contamination issues in the manufacturing process. Back in February, Mikhaela prompted me to think a little harder about them. I didn't have answers to her questions until today. Even so, I don’t have totally solid answers. Maybe you can help fill in the holes? Here’s her email and what follows is my response:
First, I want to say thank you for your amazing cookbooks and recipes. Your recipes and in-depth tips have allowed me to make food for my food-allergic daughter that she can never eat in a restaurant!
For example--last night I made banh mi using the sandwich recipe from Into the Vietnamese Kitchen, the Vietnamese baguette recipe from your website (we can't buy safe baguettes anywhere because my daughter is allergic to sesame, nuts, mustard, eggs and dairy... your recipe was PERFECT)... and the other night we made char siu bao and potstickers with the recipes from Asian Dumplings.
Anyway, since you always seem to be hunting down ingredients and creating from-scratch recipes, I wonder if you have any thoughts on sourcing or making two items I can't seem to find safe versions of: wheat starch and rice paper sheets? I would love to make some wheat starch dough dumplings and summer rolls that my kid could eat!
I live in Brooklyn, so it is very easy for me to find wheat starch in Chinatown, but I have no idea if it is safe or contaminated with sesame or nuts... And likewise with rice paper sheets. My daughter is so sensitive to cross-contamination that we can't allow her to eat any product that I can't call the manufacturer about and make sure the factory is free from cross-contamination.
Is it possible to make wheat starch as part of the process of making seitan? Most wheat gluten recipes I've seen just discard the water... I'm assuming that's where all the starch and bran end up?
Would the rice sheet recipe in Asian Dumplings work for making Vietnamese summer rolls? Or would I need to do something different?