From the Maryland Office of Seafood Marketing comes:

Chesapeake Oysters Rockefeller

3 doz Maryland oysters in shell
1 ten-ounce pkg frozen chopped spinache, cooked
1 tbls parsley flakes
1/4 tsp lemon and pepper seasoning
6 drops hot sauce
1 tbls instant minced onion
1/4 tsp celery salt
1/2 cup dry bread crumbs
1/2 cup butter or margarine, melted
Grated Parmesan/Romano cheese for topping, if desired

Open oysters, letting oysters remain in deep half of shell; discard other half. Fine chop spinach. Mix rest of engredients, except cheese, with spinach. Spread mixture on top of oysters. Sprinkle cheese over top if desired.

Arrange oysters in a single layer in shallow baking pan. Bake in preheated 400 degree oven for 10 minutes or until top is hot and bubbly.

Makes 3 dozen.

If you can't find whole oysters, but can get already shucked ones, an alternative might be

Oysters Casino

3 slices bacon, chopped
1 small onion, chopped
1 small stalk celery, chopped
1 tsp lemon juice
1 tsp salt
1/8 tsp pepper
6 drops Worchestershire
4 drops hot sauce
1/4 tsp seafood seasoning
1 pint shucked Maryland standard oysters, drained

Fry bacon until partially cooked. Add onion and celery and cook until tender. Add lemon juice and seasonings.

Arrange oysters in a single layer in foil-lined shallow baking pan. Spread bacon mixture over oysters. Bake at 400 degrees until edges of oysters begin to curl, about 10 minutes.

Makes about 3 dozen appetizers or serve on toast, with liquid, as an entree. Makes 4 servings.