Grilled Tuna Steaks with Asian Sesame Crust

Gather the ingredients.

In a large zip-top bag, combine the soy sauce, chopped scallions, lemon juice, sesame oil, and fresh ginger. Swish everything around in the bag until it's well combined. Add the tuna steaks, turning to coat them completely with the marinade. Press the excess air out of the bag, seal, and marinate in the refrigerator for about 20 minutes. Preheat the grill to high heat; this can be a countertop contact grill, an open grill pan, or an outdoor gas or charcoal grill. If using a contact grill, set to "sear" or the highest temperature setting. Place the sesame seeds on a plate or a shallow dish. Remove the tuna steaks from the marinade, brushing the scallions off the steaks; reserve the marinade. One at a time, coat the steaks in sesame seeds on all sides, pressing the seeds onto the steaks so they'll stick.

Spray the grill plates lightly with nonstick spray and place the steaks on the grill. If using a contact grill, close the cover so the top grill rests evenly on the steaks; do not press down. Grill for about 3 minutes for a rare, pink interior; grill longer if you prefer your tuna cooked through.

If you are using an open grilling surface, carefully flip the tuna steaks with a pair of tongs after 3 minutes and cook for 3 minutes on the other side. Remove the steaks from the grill and keep warm.

While the tuna cooks, pour the marinade into a small saucepan and bring to a boil. Mix the cornstarch with the water to create a slurry and add to the saucepan, stirring with a whisk. Simmer for about 3 to 4 minutes, until the sauce thickens.

To serve, slice the tuna steaks on the diagonal into thin pieces. Fan the slices on a plate and drizzle with the sauce.