Prepare the Cream Sauce:
- Melt butter in a medium saucepan over medium heat. Add flour and cook, stirring constantly, for about 2 minutes until lightly toasted.
- Gradually whisk in clam juice and milk, ensuring a smooth consistency.
- Season with kosher salt and black pepper. Increase heat to medium-high and bring to a boil, stirring frequently. Reduce to a simmer and cook for 8–10 minutes until thickened. Adjust seasoning as needed.
2. Cook the Lasagna Noodles:
- Bring a large pot of salted water to a boil. Add lasagna noodles and cook until al dente according to package instructions.
- Drain and rinse under cool water to prevent sticking. Arrange on a baking sheet, lightly coating with olive oil. Set aside.
3. Sauté the Seafood:
- Melt butter in a large skillet over medium heat. Add garlic and cook until fragrant, about 3 minutes.
- Pour in white wine and cook until almost evaporated, about 3 minutes.
- Add shrimp and cook until pink and just cooked through, about 4 minutes.
- Stir in parsley, lemon juice, and kosher salt. Taste and adjust seasoning as needed.
4. Prepare the Ricotta Mixture:
- In a medium bowl, combine ricotta cheese, grated Parmesan, kosher salt, and black pepper. Stir until smooth. Taste to ensure proper seasoning.
5. Assemble the Lasagna:
- Spread 1/2 cup cream sauce on the bottom of a greased 9×13-inch baking dish.
- Arrange one-third of the noodles over the sauce, overlapping slightly.
- Spread half the ricotta mixture over the noodles, followed by half the shrimp mixture, half the lobster, and half the crab. Sprinkle with 1 cup mozzarella and dollop with 1 cup cream sauce.
- Repeat layers with remaining noodles, ricotta mixture, seafood, mozzarella, and cream sauce.
- Top with a final layer of noodles, spread remaining cream sauce evenly, and sprinkle with remaining mozzarella.
6. Bake the Lasagna:
- Preheat oven to 350°F (175°C).
- Coat a large sheet of aluminum foil with cooking spray and cover the lasagna loosely, spray-side down.
- Bake for 30 minutes. Remove foil and bake for an additional 20–25 minutes, or until the top is golden and bubbly.
- Let cool for at least 15 minutes before slicing. Garnish with reserved parsley.