Active Time

　　45 min

　　Total Time

　　2 1/2 hr

　　Before tasting the oysters served by Tadashi Ono at New York's Matsuri, I was convinced that the best oyster is a naked one. But there is something magical about the way frozen ponzu brings out the sweetness of a plump oyster; add the crunch of tobiko and you have something absolutely extraordinary.

　　In our version, we serve the oysters on a bed of seaweed to keep them flat and to retain their liquor. If you can't find seaweed, substitute a bed of uncooked sushi rice. Traditional ponzu (a soy citrus sauce) is made with fish stock (dashi), but we used a kelp broth instead because we found the stock too heavy.

　　

Ingredients

Makes 6 hors d'oeuvre servings

　　

For ponzu granita

1 (1-inch-wide) piece kombu (dried kelp), rinsed

　　1 cup water

　　3 tablespoons mirin (Japanese sweet rice wine)

　　3 tablespoons soy sauce

　　3 tablespoons rice vinegar (not seasoned)

　　2 tablespoons fresh or bottled yuzu juice

　　1 teaspoon sugar

　　

For oysters

18 small oysters (preferably Kumamoto or Prince Edward Island), not shucked

　　1 oz tobiko (flying-fish roe)

　　1 oyster knife

　　Garnish: a bed of seaweed (1 lb)

　　

Special Equipment

a protective glove; an oyster knife

　　

Make granita:

Step 1

Bring kombu and water to a simmer in a small saucepan over moderate heat, then remove from heat and cool completely, about 30 minutes. Discard kombu. Transfer 5 tablespoons kombu broth to a bowl along with remaining granita ingredients and stir until sugar is dissolved. (Reserve remaining broth for another use.)

　　

Step 2

Pour granita mixture into an 8-inch metal baking pan and freeze, stirring and crushing lumps with a fork every 20 minutes, until evenly frozen, about 1 hour. Scrape with a fork to lighten texture, crushing any lumps.

　　

Open oysters and assemble dish:

Step 3

Wearing protective glove, hold an oyster, flat side up, and open it at its narrow point with oyster knife. Loosen oyster from top shell with oyster knife if necessary, discarding top shell, then loosen oyster meat within curved bottom shell, keeping it in shell. Discard any loose bits of shell. Arrange oyster on bed of seaweed and repeat with remaining oysters in same manner.

　　

Step 4

Top each oyster with a scant 1/4 teaspoon tobiko. Serve granita on the side.

　　Cooks' notes:

　　• Oysters can be opened and arranged on platter with tobiko 2 hours ahead and chilled, loosely covered. • Granita can be made 2 days ahead and frozen, covered. Scrape again before serving.