Here is the recipe:
300g sashimi grade yellowfin tuna
2 Tbs olive oil
salt and pepper
1 Tbs red chilli, chopped
2 Tbs watercress
Tataki sauce: 1 green scallion, sliced
1/2 tsp ginger paste(or grated fresh ginger)
2 Tbs light soy sauce
1 tspsesame seeds
1 tsp sesame oil
1 Tbs mirin
juice from half a lime
Season the tuna with salt and pepper on all sides.
Heat olive oil in a non stick pan, and when the oil is hot, add the tuna and sear it 30 seconds on each side. When all sides are seared, remove from the heat and let it cool down on a plate in the fridge.
Meanwhile, combine all the Tataki sauce ingredients in a small bowl.
Slice the tuna, placing all the slices on a plate, pour the sauce over and garnish with watercress and chopped chilli.