Preheat oven to 400 degrees F.
Melt the butter in a skillet over high heat. Stir in the flour and cook, stirring constantly, for 1 minute. Whisk in the milk, a little at a time, then season with salt and pepper. Bring the mixture to a boil and then reduce the heat to medium-low. Simmer for 4 to 6 minutes. Remove from heat and stir in 1/2 cup of the cheese.
In a bowl combine the oysters, shrimp and crawfish, and season with salt and pepper. Stir in the milk mixture, season, and mix well. Lightly grease 12 individual pie tins. Spoon the mixture into each pie tin and sprinkle each with the remaining cheese. Bake for 8 to 10 minutes or until bubbly. Remove from oven and serve warm.
Yield: 12 servings