Lay out the beef brisket slices on a plate with paper towels and season with herb salt.

Wash 2 cups of white rice and cook in a rice cooker with slightly less water than the standard measurement. Add kombu pieces for flavor.

Thinly slice the onion and soak in cold water for 10 minutes to remove bitterness. Drain well.

Chop green onions finely. You can substitute with sprouts if preferred.

Mix sugar, vinegar, and salt for sushi vinegar. Heat in the microwave for 20 seconds to dissolve completely.

Once the rice is cooked, mix in the sushi vinegar one spoonful at a time while the rice is still hot.

Shape the rice into sushi bases and top with a small amount of wasabi. Wet your hands if the rice sticks.

Pan-fry the beef brisket slices on medium heat without oil until cooked. Place one slice on each sushi base.