- 3/4 cup plus 1 tablespoon safflower oil, plus more for brushing
- 1/2 cup thinly sliced fresh ginger
- 3 medium shallots, thinly sliced
- 3 large garlic cloves, thinly sliced
- 1 cup fresh red grapefruit juice
- 1 cup fresh orange juice
- 1/3 cup fresh lemon juice
- 3/4 cup dry white wine
- 3 tablespoons light soy sauce
- 2 cups chicken stock or canned low-sodium broth
- Six 1-inch-thick tuna steaks (about 2 1/4 pounds total)
- Salt and freshly ground pepper
- 1/4 cup wasabi paste
In a large skillet, heat 1 tablespoon of the safflower oil until shimmering. Add the sliced ginger, shallots and garlic and cook them over moderate heat until softened, about 3 minutes. Add the red grapefruit, orange and lemon juices along with the wine, light soy sauce and stock and bring to a boil over high heat. Cook until the sauce is reduced to 1/2 cup and is slightly syrupy, about 40 minutes.
Set a fine-mesh sieve over the jar of a blender. Strain the sauce, pressing on the solids to extract the liquid. With the blender on, slowly pour in the remaining 3/4 cup of oil until combined.
Light a grill or heat 2 grill pans. Lightly brush the tuna steaks with oil and season with salt and pepper. Grill the steaks over moderately high heat, turning once, until medium rare, about 6 minutes. Transfer the steaks to plates, spoon the sauce on top and serve with the wasabi on the side.