The Darby's Oysters Rockefeller
- 48 small to medium oysters, such as Wellfleet or Beau Soleil, scrubbed
- 1 cup (2 sticks) unsalted butter, cut into 1/2-inch slices
- 6 medium shallots, peeled and thinly sliced
- Coarse salt
- 3/4 cup all-purpose flour
- 1/2 cup Herbsaint
- 4 cloves garlic, finely grated
- 1 tablespoon finely chopped oil-packed anchovy fillets, in their oil
- 1 1/2 cups heavy cream
- 1 pound baby spinach, stemmed, washed, and chopped
- 1 pound fresh watercress, stemmed, washed, and chopped
- 2 sprigs fresh basil, chopped
- 2 sprigs fresh tarragon, chopped
- 1/2 cup freshly grated Parmesan cheese
- 1/4 cup toasted panko
- 1/4 cup dried breadcrumbs
- 2 scallions, trimmed, white and light green parts only, thinly sliced
- Juice of 1 to 2 lemons
Preheat the oven to 375 degrees.
Place a strainer over a medium bowl; gently shuck the oysters over the strainer, using the strainer to catch the meat and strain the liquor into the bowl. Reserve the deeper halves of each oyster shell (discarding remaining shells) and scrub clean under cold running water; dry shells and arrange in a single layer on a baking sheet; set aside.
In a medium skillet, melt butter over medium heat. Add shallots; season with salt and cool until tender, 3 to 5 minutes. Stir in flour. Add Herbsaint and cook until almost all the liquid has evaporated. Add garlic and anchovies and their oil; stir to combine. Season with salt. Add heavy cream and reserved oyster juices; let cook 1 minute. Stir in spinach, watercress, basil, and tarragon. Cook until mixture thickens, 3 to 5 minutes. If mixture seems too thick, add a little water or heavy cream to thin.
Place reserved oyster shells in oven and bake until warm, about 2 minutes. In a medium bowl, mix together cheese, panko, and breadcrumbs until well combined; set aside.
Spoon scant tablespoon spinach mixture into each of the shells and top each with a whole oyster. Top with a little more of the spinach mixture and sprinkle with the breadcrumb mixture. Transfer to oven and bake until oysters are warm to the touch, 2 to 3 minutes.
Preheat broiler. Place oysters under broiler to brown. Garnish with scallions and season with lemon juice; serve immediately.