1/2 cup soy sauce
1/4 cup mirin or rice vinegar
1 small shallot, thinly sliced
1/2 jalapeño, seeded and chopped
2 tablespoons fresh orange juice
One 3-inch strip of lemon zest plus 1 tablespoon fresh lemon juice
1 teaspoon sugar
1/4 teaspoon ground coriander
1 tablespoon vegetable oil
Four 4-ounce tuna steaks, 1 inch thick
Salt and freshly ground pepper.
In a small saucepan, combine the soy sauce, mirin (or rice vinegar), shallot, jalapeño, orange juice, lemon zest and juice, sugar and coriander. Simmer over moderate heat until reduced by half, about 8 minutes. Strain the sauce.
In a large nonstick skillet, heat the oil until shimmering. Season the tuna with salt and pepper. Cook over high heat for 1 minute per side. Transfer the tuna to a platter and let rest for 1 minute; thickly slice and serve with the sauce.
If you are a fan of seared tuna (and we are!), you can try this recipe  as well.