Preheat your oven to 200°C (400°F). If you have them, arrange a baking sheet with a rim or a cast-iron skillet. You will use this to hold the oysters steady.

Spread a thick layer of coarse sea salt or kosher salt onto the prepared baking sheet or into the skillet. This salt bed will help to stabilize the oysters and ensure even cooking.

Arrange the shucked oysters, on the half shell, onto the salt bed. Ensure they are nestled securely and are sitting relatively flat. They should contain their natural liquor.

In a medium saucepan, melt the unsalted butter over medium heat. Add the finely minced shallots and cook until softened and translucent, about 3-4 minutes. Be careful not to brown them.

Add the minced garlic to the saucepan and cook for another minute until fragrant. Again, avoid browning the garlic, as it can turn bitter.

Stir in the finely chopped, blanched spinach. Cook for about 2 minutes, allowing it to heat through and combine with the shallot and garlic mixture.

Remove the saucepan from the heat. Stir in the Pernod (or Anisette), Worcestershire sauce, chopped parsley, and chopped chives. Mix until everything is well combined.

Stir in the finely grated Parmesan cheese and the breadcrumbs. Mix until you have a thick, creamy, spreadable mixture. Season with salt and freshly ground black pepper to taste.

Carefully spoon a generous portion of the spinach mixture onto each oyster, ensuring good coverage. You want about 1 to 2 tablespoons of topping per oyster, depending on its size.

Place the baking sheet or skillet with the topped oysters into the preheated oven. Bake for 10-15 minutes, or until the topping is heated through, lightly golden brown, and the edges of the oysters are bubbling.

Carefully remove the baking sheet from the oven. Let the oysters rest for a minute or two before serving. They will be very hot.

Serve the Oysters Rockefeller immediately. You can garnish with a sprinkle of fresh parsley or chives if desired. Serve with lemon wedges on the side.