Gwa Kao, sometimes labeled Taco Buns, are found in the cold case with the noodles in my local Asian market. I bought them to serve a Momofuku-type pork belly, but have discovered they have other uses as well. Pop a Gwa Kao in the microwave for 30 seconds and it will emerge steaming hot but still well formed and not wilting or sticking to itself as an American bun would. The secret is probably the undefined “emulsifiers” listed on the ingredient list.
Anyway, I have been employing these to make leftover ham mini-sandwiches with my Jones Dairy Farm ham and pickled ramps. Squirt on some Sriracha and hoisin and you’re good to go. They’re about half the size of a burger bun, so takes two to make a meal.