Preheat Oven: Preheat your oven to 375°F (190°C).

Cook Spinach: In a skillet, heat a tablespoon of olive oil over medium heat. Add spinach and cook until wilted. Set aside.

Prepare Shrimp: In the same skillet, add another tablespoon of olive oil and sauté the onion and garlic until transparent. Add shrimp and cook until they turn pink. Season with salt and pepper. Remove from heat.

Make Bechamel Sauce: In a saucepan, melt butter over medium heat, then add flour and whisk to combine. Gradually pour in milk and cream, stirring continuously until the sauce thickens. Season with salt, pepper, and a pinch of nutmeg. Remove from heat.

Assemble Lasagna: Spread a thin layer of bechamel sauce on the bottom of a 9×13 inch (23×33 cm) baking dish. Place three lasagna sheets over the sauce. Layer with half of the ricotta cheese, half of the shrimp-spinach mixture, and 1/3 of the mozzarella cheese. Pour 1/3 of the bechamel sauce over. Repeat the layers, ending with lasagna sheets topped with the remaining bechamel sauce and the rest of the mozzarella and Parmesan cheese.

Bake: Cover with aluminum foil and bake for 25 minutes. Remove foil and bake for an additional 15 minutes or until the cheese is golden and bubbly.

Garnish and Serve: Let it cool for about 15 minutes before serving. Garnish with freshly chopped parsley.