Ingredients

  • 1/4 cup kosher salt
  • 2 (10-ounce) bags fresh spinach, coarse stems discarded
  • 2 leeks (white and pale green parts only), quartered lengthwise and thinly sliced crosswise
  • 1 tablespoon olive oil
  • 3 ounces slab or thick-sliced bacon, cut into 1/4-inch dice
  • 1 shallot, quartered lengthwise and thinly sliced crosswise
  • 1 garlic clove, minced
  • 1 day-old baguette, crust discarded and bread coarsely ground in a food processor (2 cups)
  • 2 tablespoons finely chopped fresh chervil
  • 2 tablespoons finely chopped fresh chives
  • 2 tablespoons finely chopped fresh flat-leaf parsley
  • 2 tablespoons finely chopped fresh tarragon
  • Finely grated zest and juice of 1 medium lemon
  • 3/4 teaspoon fine sea salt, or to taste
  • Rounded 1/4 teaspoon white pepper, or to taste
  • Pinch of freshly grated nutmeg, or to taste
  • 1 stick (1/2 cup) unsalted butter, melted
  • About 10 cups rock or kosher salt for baking and serving (3 pounds)
  • 40 oysters on the half shell
  • Accompaniment: lemon wedges

Method

  • Preheat oven to 500F.
  • Bring a 6- to 8-quart pot three-fourths full of water to a boil with kosher salt, then stir in spinach and cook 30 seconds.
  • Transfer with a slotted spoon to a large bowl filled with ice and cold water to stop cooking.
  • Drain spinach and squeeze dry, then finely chop.
  • Wash leeks well in a bowl of cold water, then lift out and drain well.
  • Heat oil in a 10-inch heavy skillet over moderately high heat until hot but not smoking, then saute bacon, stirring, until golden and just cooked through (but not crisp), about 3 minutes.
  • Transfer with slotted spoon to paper towels to drain.
  • Add leeks, shallot, and garlic to fat in skillet and cook over low heat, covered, stirring occasionally, until softened, about 8 minutes.
  • Toss together leek mixture, spinach, bacon, bread crumbs, herbs, lemon zest and juice, sea salt, white pepper, nutmeg, and butter in a large bowl with a fork.
  • Spread 2 to 3 cups rock salt in each of 2 large shallow baking pans and nestle oysters (in shells) in it.
  • Spoon a heaping tablespoon bread-crumb stuffing loosely on top of each oyster.
  • Bake in batches in upper third of oven until golden, about 6 minutes.
  • Serve warm oysters in shells on plates lined with rock salt.