Ingredients

  • 1 1/4 pounds fresh, thick blackfish fillets
  • 6 medium-to-large ripe tomatoes (about 2 1/2 pounds)
  • 1 small cucumber (about 6 ounces), peeled, seeded, and cut into 1/4-inch dice (1 cup)
  • 4 radishes, cleaned and cut into 1/4-inch dice (1/2 cup)
  • 4 scallions, cleaned and minced (1/2 cup)
  • 2 cloves garlic, peeled and finely chopped (1 teaspoon)
  • 1/2 cup loose coriander leaves
  • 2 tablespoons mustard
  • 1 1/2 tablespoons red-wine vinegar
  • 1 teaspoon Lea & Perrins Worcestershire sauce
  • 13 cup corn or olive oil
  • 1/2 teaspoon salt
  • 1/2 teaspoon freshly ground black pepper

Method

  • Arrange the fish on a plate and place in a steamer.
  • Place on the stove and bring to a boil.
  • Steam for six to eight minutes, until the fish just flakes but is still quite moist and barely cooked.
  • Let cool to room temperature and then flake, separating the fillets into one-inch pieces.
  • You should have approximately two cups.
  • Cut off the top third of each tomato and press each base lightly to extract a little of the juice and seeds.
  • Using a measuring tablespoon (because it has sharp edges), remove the inside of each tomato base and top.
  • (This flesh, and the ''lids,'' will amount to approximately one and a quarter pounds and can be used in the bean recipe instead of the plum tomatoes.)
  • To make the vinaigrette, combine the mustard, red-wine vinegar, Worcestershire sauce, oil, salt and pepper in a bowl and mix well.
  • Add the cucumber, radish, scallion and garlic to the vinaigrette and stir to combine.
  • Gently fold in the fish and coriander so as not to break the fish too much.
  • Arrange the tomato receptacles in a gratin dish and stuff lightly with the fish mixture, heaping the filling.
  • Cover with plastic wrap and refrigerate until time for the picnic.
  • (The tomatoes can be stuffed a few hours ahead and refrigerated, but should be eaten at room temperature for best flavor.)