The Japanese have a knack with fish. Techniques are simple, sauces clean and vibrant. Here is one that takes moments to put together, and moments to consume, happily. Serve with rice and snap peas, spinach, or Japanese eggplant.
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.
© 1992 Joyce Goldstein. All rights reserved.