Ingredients

• For the Filling

  • 4 tablespoons unsalted butter
  • 1/2 medium onion, chopped
  • 1 fennel bulb (8 ounces), halved, cored, and very thinly sliced, preferably on a mandoline
  • 1/4 cup all-purpose flour
  • 2 cups fish stock
  • 1/2 cup water
  • 1 pound cooked lobster meat (from 2 lobsters), cut into 1-inch pieces
  • 3/4 cup fresh shelled or frozen English peas
  • 3 tablespoons heavy cream
  • 1 tablespoon fresh tarragon
  • Coarse salt and freshly ground pepper

• For the Topping

  • 4 tablespoons unsalted butter
  • 6 slices Pullman bread (1/2 inch thick)