Melt 1/2 cup butter, stir in 3/4 cup flour, and stir the roux over rather high heat for about 5 minutes, until it turns a rich dark brown.
Add 1 tablespoon paprika, 1 teaspoon salt, and 1/2 teaspoon freshly ground black pepper, and cook, stirring, for 3 minutes longer.
Add 4 tablespoons each of finely chopped onion and green pepper and 1/2 teaspoon finely chopped garlic.
Cook slowly for 5 minutes longer, stirring constantly. Remove the pan from the heat and stir into the mixture 2 tablespoons lemon juice and 1 tablespoon Worcestershire sauce.
Poach 1 quart oysters in their own juices for 2 minutes.
Combine oysters and liquor with the vegetables.
Pour into a baking dish, sprinkle with 2 tablespoons crushed cracker crumbs, and bake in a hot oven (400° F) for 30 minutes.