Tuna with Orange, Ginger and Lemongrass Sauce

Ingredients 
3/4 cup,  plus 2 tablespoons fresh orange juice
1 teaspoon cornstarch
2 tablespoons olive oil
1/4 cup finely chopped onion
2 tablespoons minced peeled fresh ginger
2 tablespoons minced fresh lemongrass*
1 tablespoon minced garlic
1/4 teaspoon dried crushed red pepper
1/4 cup chicken stock or canned low-salt chicken broth
1 tablespoon soy sauce
4 6- to 7-ounce tuna steaks
Additional olive oil
8 teaspoons sesame seeds

Directions
Whisk 2 tablespoons orange juice and cornstarch in small bowl to blend. Heat 1 tablespoon oil in medium nonstick skillet over medium-high heat. Add onion, ginger, lemongrass, garlic and crushed red pepper; sauté until onion is light golden, about 3 minutes. Add 3/4 cup orange juice, stock and soy sauce and boil until reduced to 3/4 cup, about 4 minutes. Whisk in cornstarch mixture; boil 1 minute. Remove from heat. Season sauce to taste with salt and pepper. 

Brush tuna steaks with olive oil. Coat each side of each tuna steak with 1 teaspoon sesame seeds, pressing gently to adhere. Heat 1 tablespoon olive oil in large nonstick skillet over high heat. Add tuna and cook until opaque in center, about 3 minutes per side. Bring sauce to simmer. Transfer tuna to plates. Serve with sauce.  Makes 4 servings.
*Available at Asian markets and in the produce section of some supermarkets.

Source:  Bon Appétit