Serves 4 to 6, depending on serving size. Recipe is from Oysteria.
2 dozen oysters, with all their liquid
1 bottle clam broth
2 sticks butter, cubed
1 cup flour
1 cup onions, minced
3 tbls. sweet anchovy paste
1 tbl. garlic, chopped
1½ lbs. fresh watercress, patted dry, trimmed and finely chopped
1½ lbs. fresh spinach, washed, patted dry, trimmed and freshly chopped
Salt and pepper to taste
1½ cup Herbsaint
½ cup grated Parmesan cheese
1. Preheat oven to 400 degrees. Drain the oysters and liquid through a fine mesh strainer. (You should have about 3 cups of oyster liquid; if not enough supplement with clam broth.).
2. In a large sauté pan, melt the butter over medium heat. Stir in the flour and cook for four minutes. Stir in the onions and cook for 2 minutes. Stir in the anchovy paste, garlic, watercress and spinach. Season with salt and pepper. Cook for 1 minute.
3. Stir in the oyster liquid and bring up to a boil. Reduce to a simmer and continue to cook for 8 to 10 minutes or until the sauce is thick. Remove from heat and stir in the Herbsaint. Add more salt and pepper if needed.
4. Spread rock salt evenly over a large sheet pan. Arrange the oyster shells on baking sheet and place oysters back in their shells, unless you are using an oven-safe oyster plate, in which case place them in the shells on the plate. Season with salt and pepper and place a heaping spoonful of filling on top of each oyster. Using the back of a spoon, gingerly pat the filling into the shell.
5. Sprinkle the top of the oyster with grated cheese. Place the baking sheet or oyster plate in the oven and cook for 15 minutes or until the sauce is golden brown and the oysters have curled.
Serve with fresh lemons.