Ingredients2 Tbs. unsalted butter
1 tsp. minced ginger root
Salt and freshly ground white pepper
1-1/2 lbs. best-quality ahi tuna
6 cups loosely packed mizuna (mih-ZOO-nuh) greens, curly endive or red leaf lettuce (Mizuna is a feathery, delicate salad green. It can be found from spring to summer in farmer's markets or specialty produce markets. Sometimes you find it in mesclun, a special salad-green mix.)
1 cup marinated shiitake mushrooms, for optional garnish (recipe follows)
2 Tbs. finely chopped chives, for garnish
Melt butter over low heat; stir in minced ginger root and remove from the heat. Allow mixture to infuse for 2 to 3 hours or overnight for the flavor to develop. Reheat butter-and-ginger infusion until soft enough to spread easily. Brush each sheet of aluminum foil with some of this mixture and sprinkle with a little kosher salt and freshly ground white pepper. With a very sharp knife, slice the 1-1/2 pounds ahi tuna about 3/8" thick against the grain and lay 2 slices in a single layer on each piece of foil. Preheat a grill, griddle, or large heavy skillet to very high heat. Transfer the sheets of foil to the hot grill and cook for about 30 seconds, or until the tuna is seared on one side and still raw on the other. Immediately transfer the tuna slices, raw side up, to the plates and drape them loosely around the edges of the salad. Garnish with 2 tablespoons chopped chives and 1 cup marinated shiitake caps, if desired, and serve immediately.