Stab 360 g beef steak with a clean fork on both sides, dry with kitchen paper and sprinkle each side with a pinch of salt and pepper.
Place 2 dried bay leaves, 2 stalks fresh rosemary and 4 stalks fresh dill on the top.
Spread half of the grated onion over the bottom of a container, place the steak on top and then cover the top with the other half. Cover with a lid or plastic wrap and store in a cool place for 30 minutes. (Preferably, not a refrigerator as this slows down the tenderisation process.)
Mix 2 tbsp Japanese soy sauce (koikuchi shoyu), 1 tbsp mirin, 1 tbsp red wine, 1 tsp ginger paste and 1 tsp garlic paste in a small saucepan. Place on a medium heat and bring to a boil, allow to bubble for 1 minute and then remove from the heat. Set aside for later.
Once 30 minutes have passed, start heating your oil to 180 °C (356 °F). While you wait, scrape the grated onion and herbs off of the steak. Wash the surface with cold running water and then pat dry with a paper towel.
Coat the steak with a thin layer of 4 tbsp all-purpose flour all over.
Whisk 1 egg with 1 tbsp milk and 1 tsp cooking oil until smooth, then coat the steak.
Finally, coat the steak with a generous layer of 100 g panko breadcrumbs. Gently press them down with your palm to secure them.
Once the oil is preheated, deep fry steak for 1 minute and a half, turning it over halfway through. In other words, 45 seconds on each side. (For medium rare, you can increase this to one minute on each side, 2 minutes in total.)
Transfer to a wire rack and allow to rest for 3 minutes. Cut into strips, approx 1.5cm thick (1/2 inch).
Serve with dipping sauce (or wasabi/salt) and enjoy!
Notes
This recipe doesn't work for chicken or pork as they need different oil temperatures and cooking times. Refer to my Pork Tonkatsu and Crispy Chicken Katsu recipes for more info.