Marinade

• 2 tablespoons sake
• 2 tablespoons fresh lime juice
• 1 teaspoon grated lime zest
• 1 tablespoon soy sauce
• 2 tablespoons mild olive oil
• 4 pieces yellowfin tuna fillet, about 6 ounces each and ¾ to 1 inch thick

Wasabi Butter

• 1 tablespoon wasabi powder
• 1 tablespoon sake
• 8 tablespoons unsalted butter, softened
• Olive oil for brushing the fish
• Salt and freshly ground pepper

Procedure

For the marinade, combine all the ingredients in a shallow nonaluminum container. Turn the tuna fillets in the marinade and let stand about 30 minutes.

For the wasabi butter, mix the wasabi with the sake to make a paste. Let rest 20 minutes and then beat the paste into the softened butter (see note). Season with salt and pepper.

Heat a grill or broiler. Brush the tuna lightly with oil, sprinkle with salt and pepper, and grill or broil to medium rare. 2 to 3 minutes each side. Transfer to serving plates and place 1 tablespoon wasabi butter on each piece of tuna. Serve hot.