How to Make It
Preheat the oven to 400°. In a small saucepan of boiling water, blanch the scallions for 2 minutes. Drain and rinse under cold water. Set a rack on a baking sheet and arrange the shiitake caps on the rack, gill sides down. Season lightly with salt and pepper.
Season the steak with salt. In a food processor, coarsely grind the nori with the sesame seeds, red pepper and 1 teaspoon black pepper. Spread the nori mixture on a plate and dredge the steak in it.
In a medium skillet, heat 1 tablespoon of the olive oil until shimmering. Add the steak and cook over moderately high heat until the nori is toasted, about 4 minutes per side. Place the steak over the mushrooms and roast for about 15 minutes, or until an instant-read thermometer inserted in the center of the meat registers 130° for medium rare. Transfer the steak to a cutting board and let rest for 10 minutes.
Meanwhile, halve the scallions lengthwise and quarter the mushroom caps. In a small bowl, whisk the tamari with the mirin, lemon juice and the remaining 1/2 tablespoon of olive oil.
Slice the steak 1/4 inch thick and arrange it on plates with the shiitake mushrooms and scallions and a small mound of wasabi. Drizzle the tamari sauce over the steak and serve.
One Serving 256 cal, 11 gm fat, 2.5 gm saturated fat, 11 gm carb, 3 gm fiber.