Add all the ingredients to a small saucepan, bring to a gentle boil and reduce to a simmer for 5 minutes over a low heat . When the garlic and ginger are softened and the sauce has slightly thickened - pass through a fine sieve, allow to cool and serve at room temperature.
To Make Katsu Burgers.
Over a medium heat place a small frying pan with a dash of oil. When hot, add the onions and cook until soft and golden, about 5 minutes. Set aside to cool.
In a small bowl mix the dashi powder with a small handful of panko breadcrumbs and the milk.
Place the minced beef and pork in a large mixing bowl, add the Worcestershire sauce, sesame oil, soy, tonkatsu sauce and the egg yolks. Then add the softened breadcrumb mix and onions, season well mixing everything thoroughly. Divide into 6 portions and shape into burgers with your hands.
Prepare the coating station. 1 bowl of whisked eggs, 1 bowl of seasoned flour, 1 bowl of breadcrumbs.
Coat each burger with flour, drench in egg and coat in breadcrumbs. Leave them in the fridge to chill until needed.
To cook: heat a large pan of oil to 170c,deep enough to deep fry the burgers. Fry for 8-10 minutes turning every couple of minutes until golden and crispy, drain onto kitchen paper.
Serve the burgers in a toasted brioche or seeded bun on a bed of shredded cabbage, drizzled with tonkatsu sauce,
Epic - East meets West.