Preheat your oven to 375°F (190°C).

Cook the lasagna noodles according to package instructions until al dente. Drain and set aside.

In a large skillet, heat olive oil over medium heat. Add minced garlic, and sauté until fragrant (about 1 minute).

Add the shrimp to the skillet and cook until they turn pink (about 3–4 minutes). Stir in the fresh spinach and cook until wilted. Season with salt and pepper. Remove from heat and set aside.

In a small saucepan, melt the butter over medium heat. Stir in the flour and whisk for 1-2 minutes until combined. Gradually add the heavy cream while whisking constantly to avoid lumps. Cook until the sauce thickens (about 5–7 minutes). Add nutmeg, salt, and pepper to taste.

In a mixing bowl, combine the ricotta cheese, half of the mozzarella cheese, and half of the Parmesan cheese. Mix well.

To assemble the lasagna, spread a layer of the white sauce on the bottom of a baking dish. Place 4 lasagna noodles over the sauce.

Spread half of the ricotta cheese mixture over the noodles, followed by half of the shrimp and spinach mixture, and a layer of white sauce.

Repeat the layers, placing another 4 noodles, the remaining ricotta mixture, the remaining shrimp and spinach mixture, and more white sauce.

Top with the last 4 noodles, the remaining white sauce, and finally, sprinkle the remaining mozzarella and Parmesan cheese on top.

Cover the baking dish with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 20 minutes or until the cheese is bubbling and golden brown.

Allow to cool for about 10-15 minutes before slicing and serving.