Prepare the Crepe Batter: In a mixing bowl, whisk together sifted all-purpose flour, eggs, and milk until smooth. Let the batter rest for 30 minutes. Heat a non-stick skillet over medium heat, coat with melted butter, pour ¼ cup of batter, cook for 1-2 minutes, then flip and cook until golden.

Create the Béchamel Sauce: In a saucepan, melt 4 tablespoons of butter, add flour to form a roux, stir for 2 minutes, whisk in 2 cups of milk, cook for 5-7 minutes until thickened. Season with salt, pepper, and nutmeg.

Cook the Seafood Filling: In a skillet, heat oil or butter, add lobster, shrimp, and white fish, cook for 3-5 minutes. Remove from heat, fold in cheese and some béchamel sauce, adjust seasonings to taste.

Assemble the Crepes: Take a cooked crepe, place a spoonful of the seafood mixture in the center, fold sides over filling. Repeat with remaining crepes and filling in a greased baking dish.

Top with Béchamel Sauce: Spoon remaining béchamel sauce over assembled crepes, sprinkle with additional cheese if desired.

Bake for a Golden Finish: Preheat oven to 375°F (190°C), bake for 10 minutes until bubbly and golden. Let cool slightly before serving.