Combine the soy, mirin, brown sugar, sesame oil, garlic, ginger and coriander in a bowl. Add the steak; cover and refrigerate to marinade for 3 hours (or over night). Option: for a tender steak add Asian pear to the marinade see notes.
Once marinaded, remove the steaks from the marinade and reserve the liquid. Fry the steaks on both sides over medium-high heat in a good quality skillet/non stick pan until cooked to your liking. Remove them from pan and allow to rest.
Pour the reserved liquid into a smaller saucepan; bring to the boil; reduce heat and allow to simmer until the marinade has thickened and cooked through (for at least 5 minutes).
Cut the beef into strips and coat them in the reserved marinade sauce.
For The Kale Slaw:
Whisk the soy sauce, lime juice, mirin and sesame oil together in a bowl. Add the shredded and grated veggies and coat well.
For the Pico De Gallo:
Combine the tomatoes, cilantro, onions and finely diced jalapeño together in your serving dish. Drizzle with the lime juice and olive oil. Salt to taste.
For the Tacos:
Build your tacos with the greek yogurt or sour cream; Beef; Slaw and Pico De Gallo.
Notes
The Freeze Trick The secret to getting those paper thin, restaurant style beef slices is temperature. Pop your steak in the freezer for 20–30 minutes before slicing. It firms up the meat just enough to make slicing a breeze!
Don't Skip the Pear If you can find an Asian Pear, grate about 1/2 cup into the marinade. It contains an enzyme called calpain that naturally tenderizes the meat, making even tougher cuts melt in your mouth. Kiwi fruit works too, but only marinate for max 4 hours if using kiwi!.
Avoid Boiled Meat When searing the beef, cook it in batches. If you crowd the pan, the temperature drops, and the meat releases water instead of searing. You want a dark, caramelized crust that is where the flavour is!
Liquid Gold: Do not throw away the used marinade! Boiling it kills any bacteria from the raw meat and reduces it into a sticky, glossy glaze that makes these tacos addictive.
Substitutions: Not feeling beef? This marinade works wonders on chicken thighs (cut into bite-sized pieces) or thinly sliced pork tenderloin.
Make it Spicy The recipe is mild-medium. For a kick, add 1 tablespoon of Gochujang (Korean chili paste) or Sriracha to the marinade.
Warming Tortillas Cold tortillas will crack and ruin the vibe. Heat them in a dry skillet for 30 seconds per side, or wrap them in damp paper towels and microwave for 20 seconds.