Heat a large frying pan or cast-iron skillet over high heat, while seasoning the steak generously with extra virgin olive oil and salt on both sides. Carefully place the steak in the pan, and let it sear without moving it for a couple of minutes before flipping.
Continue cooking, until it is cooked to your preferred doneness. Remove it from the pan and let it rest for at least 10 minutes.
In a sauce pan, add the garlic and sesame oil to gently fry until fragrant. Pour in the soy sauce, sugar, vinegar, mirin and some white miso. Add in a handful of finely sliced spring onions, stir, and bring to the boil.
To assemble, spoon warm rice into serving bowls and top with a generous portion of your choice of crunchy vegetables, pickled ginger and pickled mustard greens. Slice the rested steak into thin strips, cutting against the grain.
Arrange the steak slices neatly over the rice and place an egg yolk in the centre. Garnish with additional spring onions, furikake, and a slice of lemon. Spoon some of the sauce over the top. Serve immediately and enjoy.