Chinese fermented black beans (known in Cantonese as dou si) are powerful little umami bombs - they add an intense, rich savouriness to whatever they're cooked with. They are made from soy beans ...

Takahiro Terada, head chef at Tsuta, a ramen restaurant in Brooklyn, N.Y.

This recipe uses feremented black soy beans, which you can find in Asian supermarkets, online and in large supermarkets. They give great flavour to the dish – far superior to anything you'll ...