I joined Vietnamese Kitchen Manager Hieu Bui on a visit to Koya, a Japanese noodle bar in Soho. We sampled a few of the treats on offer, including Braised Pork Belly in Cider, served with Hot Mustard; Skate Wing Tempura and Fennel Chips; Prawn Tempura Udon Noodle. I also tried Hieu’s recommendation, the ‘Onsen Tamago:’ a delicate Japanese variation on the humble poached egg.