Steam the soybeans until they're soft. Once cooled, mix the beans with the wheat flour to form a dough. Shape this mixture into small cakes and let them ferment for 2 days in a warm, humid environment ...

Let butter melt, and stir to combine with soy sauce. Add pasta to pan along with ½ cup reserved pasta water (or more, if the pasta looks dry). Toss until sauce thickens and coats pasta ...