Step 1: If using regular lasagna noodles, cook them according to package directions until al dente. Drain and rinse with cold water to prevent sticking, then set aside.
Step 2: Prepare the seafood. Heat 2 tablespoons olive oil in a large skillet over medium-high heat. Add the chopped onion and sauté for 3-4 minutes until softened. Add minced garlic and cook for 1 minute more until fragrant.
Step 3: Add shrimp and scallops to the skillet. Cook for 2-3 minutes, stirring occasionally, until the shrimp turn pink and scallops are opaque. Pour in the white wine and cook for another 1-2 minutes, allowing some of the alcohol to evaporate. Remove from heat, stir in the crab meat, fresh parsley, and dill. Season with salt and pepper. Set aside.
Step 4: Make the Béchamel Sauce. In a medium saucepan, melt the butter over medium heat. Whisk in the flour and cook for 1-2 minutes to create a roux, ensuring it doesn't brown. Gradually whisk in the warm milk, a little at a time, until smooth. Continue whisking constantly until the sauce thickens, about 5-7 minutes. Stir in nutmeg, white pepper, and salt. Remove from heat.
Step 5: Prepare the cheese filling. In a medium bowl, combine ricotta cheese, egg, 1/4 cup Parmesan, 1/4 cup fresh parsley, salt, and black pepper. Mix until well combined.
Step 6: Preheat your oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish.
Step 7: Assemble the lasagna. Spread about 1/2 cup of béchamel sauce on the bottom of the prepared baking dish. Arrange a layer of lasagna noodles over the sauce (trimming to fit if necessary).
Step 8: Spread half of the ricotta cheese mixture over the noodles. Top with half of the seafood mixture. Sprinkle with about 1.5 cups of mozzarella cheese. Drizzle with about 1 cup of béchamel sauce.
Step 9: Repeat the layers: noodles, remaining ricotta, remaining seafood, 1.5 cups mozzarella, and 1 cup béchamel.
Step 10: Add a final layer of noodles, then top with the remaining béchamel sauce and the remaining 1 cup of mozzarella cheese and a sprinkle of Parmesan.
Step 11: Cover the baking dish loosely with aluminum foil (you may want to spray the underside of the foil to prevent cheese from sticking). Bake for 30 minutes.
Step 12: Remove the foil and bake for an additional 15-20 minutes, or until the top is golden brown and bubbly. Let the lasagna rest for 10-15 minutes before slicing and serving. Garnish with extra fresh parsley or dill if desired.