2 teaspoons untoasted sesame seeds
2 teaspoons wasabi powder
2 teaspoons cracked black peppercorns
2 teaspoons garlic salt
1-1/2 pounds tuna loin, or 4 tuna steaks (each about 1 to 1-1/2 inches thick and 6 to 8 ounces)
2 teaspoons Asian (dark) sesame oil Wasabi Cream Sauce (recipe follows)
Sliced scallions and toasted sesame seeds, or black sesame seeds, for serving (optional)
1. Make the rub: Place the untoasted sesame seeds, wasabi powder, peppercorns, and garlic salt in a spice mill or coffee grinder and grind to a fine powder. Or place them in a mortar, and using a pestle, grind them to a fine powder.
2. Trim any skin or dark or bloody spots off the tuna. Rinse the tuna under cold running water, then blot it dry with paper towels. Place the tuna in a baking dish. Sprinkle the rub all over the tuna on both sides, patting it onto the fish with your fingertips. Drizzle the sesame oil over the tuna and rub it on with your fingertips. Let the tuna marinate in the refrigerator, covered, for 30 minutes to 1 hour.
3. Set up the grill for direct grilling and preheat to high.
4. When ready to cook, brush and oil the grill grate. Place the tuna on the hot grate and grill until cooked to taste. Grill tuna loin until the outside is nicely seared, 1 to 2 minutes per side (4 to 8 minutes in all) turning the loin with tongs. Grill tuna steaks for about 2 minutes per side for rare; 3 to 5 minutes per side for medium-rare; 4 to 6 minutes per side for medium, rotating each steak a quarter turn halfway through grilling on each side to create an attractive crosshatch of grill marks. Test for doneness using the poke method: Rare tuna will be quite soft, with just a little resistance at the surface; medium-rare tuna will be gently yielding; and medium tuna will be firm.
5. Transfer the grilled tuna to a cutting board and let it rest for 2 minutes. Carve tuna steaks into broad, thin slices, holding the knife at a 45 degree angle to the top of the fish. Carve tuna loin crosswise into 1/4-inch-thick medallions. Fan out the tuna slices on a platter or plates. Squirt zigzags of Wasabi Cream Sauce over the tuna, top with the scallions and toasted or black sesame seeds.
Wasabi Cream Sauce
Yield: Makes about 1 cup
1 to 2 tablespoons wasabi powder
1/2 cup mayonnaise (preferably Hellmann's)
1/2 cup sour cream
1 tablespoons fresh lemon juice
1 tablespoon soy sauce
Place the wasabi in a nonreactive mixing bowl. Add 1 tablespoon of cold water and stir to form a thick paste. Let sit for 5 minutes.
Add the mayonnaise, sour cream, lemon juice, and soy sauce, and whisk to mix. The mixture should be thick but pourable. If necessary, thin with a little more water. The Wasabi Cream Sauce tastes best when it is freshly made.
* Adapted from BBQ USA by Steven Raichlen (Workman Publishing).