Preheat your oven to 350°F. Grease a 9 x 13-inch baking dish and set it aside.

To make the bechamel sauce, melt the butter in a saucepan over medium heat. Add the flour and cook for a minute. Gradually pour in the milk, stirring constantly, until the sauce thickens. Mix in the parmesan cheese and then remove from heat.

For the cheese filling, combine ricotta, mozzarella, egg, dried parsley, and 1/2 teaspoon of salt in a bowl. Stir well and set aside.

Heat olive oil in a skillet over medium heat. Add the seafood mix, salt, pepper, and parsley. Cook for about 3 minutes until the seafood is done.

To assemble the lasagna, spread a layer of bechamel sauce on the bottom of the prepared baking dish. Lay some lasagna noodles over the sauce. Spread 1/3 of the cheese mixture over the noodles, followed by 1/3 of the seafood mix, and 1/3 of the bechamel sauce. Repeat the layers twice, ending with a layer of mozzarella and a sprinkle of parmesan.

Bake in the preheated oven for 35 minutes. If the top starts to brown too quickly, cover it with foil and continue baking until the cheese is fully melted.

Remove from the oven and let it rest for a few minutes before slicing and serving.