- 1 tablespoon plus 2 teaspoons soy sauce
- 1 tablespoon plus 2 teaspoons olive oil
- 1 1/4 pounds fresh tuna steak
- 4 teaspoons wasabi powder (see Note)
- 2 tablespoons tahini (sesame paste, see Note)
- 2 tablespoons rice vinegar
- 1 teaspoon Dijon mustard
- 1 teaspoon sugar
- 2 small garlic cloves, minced
- Salt and freshly ground pepper
- 7 ounces alfalfa sprouts (4 cups)
- 7 ounces trimmed enoki mushrooms (2 cups, see Note)
- 1/2 pound young spinach, stemmed
- 2 tablespoons slivered Japanese pickled ginger (see Note)
- In a shallow glass dish, combine 1 tablespoon of the soy sauce and 1 teaspoon of the oil. Add the tuna and coat well. Refrigerate for about 15 minutes, turning the fish twice.
- Light a grill or preheat the broiler. In a small bowl, mix the wasabi powder with 4 teaspoons of hot water. Cover and set aside for 5 minutes.
- In another bowl, stir 2 tablespoons of warm water into the tahini. Stir in the wasabi paste, vinegar, mustard, sugar, garlic and the remaining 2 teaspoons soy sauce and 4 teaspoons oil. Season with salt and pepper.
- Season the tuna with salt and pepper; grill or broil until crusty on the outside and rare within, about 4 minutes per side. Transfer the fish to a plate to rest for a few minutes, then slice it against the grain 1/3 inch thick.
- In a large bowl, toss the alfalfa sprouts with the enoki mushrooms and all but 2 tablespoons of the dressing; loosen the sprouts to evenly distribute the dressing. Scatter the spinach leaves on 4 large plates and arrange the tuna on top. Drizzle on the remaining 2 tablespoons dressing. Mound the sprout salad on the tuna, scatter the pickled ginger on top and serve.
Wasabi powder, tahini, enoki mushrooms and Japanese pickled ginger are available at Asian markets and health food shops.