TUNA TARTAR (about 2 cups)
1 large egg yolk
¾ teaspoon minced ginger
½ small clove garlic, finely chopped
1-1/2 teaspoons Japanese prepared hot mustard (usually sold in small tubes) or 1 teaspoon Asian dry hot mustard (usually sold in small tins or cellophane packets)
1 tablespoon mirin
1 tablespoon soy sauce
¼ cup rice vinegar
generous 1/3 cup peanut oil
2 tablespoons Asian sesame oil
¾ pound sushi grade ahi tuna fillet, cut into 1/8 inch dice
2 shallots, finely chopped
2 tablespoons snipped fresh chives, plus sixty 2 inch long pieces
salt and freshly ground pepper
30 ruffled potato chips, preferably unbroken (use tube packed ones, typically both good and unbroken) rice crackers or cucumber slices to serve
1.To make the dressing, in a food processor, combine the egg yolk, ginger, garlic, mustard, mirin and soy sauce. Process until smooth, stopping to scrape down the sides of the bowl as necessary. Add the vinegar and process for a few seconds to combine. With the motor running, very slowly drizzle in the peanut and sesame oils just until emulsified, or blended. Transfer to a bowl, cover, and refrigerate until ready to serve.
2. In a bowl, toss together the tuna, shallots, snipped chives, ½ teaspoon salt and ½ teaspoon pepper. Add enough of the dressing to moisten the mixture thoroughly and toss again. Do not add so much that the mixture is soupy, however. Reserve any remaining dressing.
3. Arrange the potato chips on a large platter and scoop a generous dollop of tuna tartar onto each chip. Gently press 2 crisscrossed chives onto the top of the tartar on each chip and serve at once.
NOTE: The dressing can be made up to 2 days in advance of serving and refrigerated. The dressed tuna is best served at once, but it can be covered and refrigerated for up to 30 minutes. If you serve it on potato chips, assemble the individua appetizers just before serving. If the chips sit with tuna on top, they become soggy.
adapted from The Williams Sonoma Cookbook