This dish is worth the effort for its originality. For something simpler, roll the tuna in crushed coriander seeds.
1/2 cup Japanese rice seasoning*
1/2 cup wasabi peas
800g tuna, trimmed and cut into 2 thick steaks
3 tbsp miso paste
2 tbsp soy sauce
2 tbsp mirin or sake
*There are numerous rice seasonings available from Asian grocery stores. The one we used has bonito, sesame seeds, dried seaweed and soy sauce as the main ingredients.
Place rice seasoning and wasabi peas in a food processor or mortar and pestle, and crush to a chunky powder. Evenly coat tuna with miso paste and press on pea mixture.
Heat a frypan with some vegetable oil over medium heat. Add tuna and cook for 2 minutes. Turn over and cook a further 2 minutes. Add soy and mirin and allow to simmer for a few seconds, basting tuna with pan juices before placing on a board and slicing into 12 pieces on an angle.
Serve with salad greens and umeboshi plums.