Preheat the oven to 190°C (375°F). Cook the lasagna noodles according to package instructions. Drain and set aside.

Heat olive oil in a skillet over medium heat. Sauté minced garlic until fragrant, about 1 minute. Add shrimp and cook until pink and opaque, approximately 3-4 minutes. Add crab meat, season with salt, black pepper, and optional red pepper flakes, and cook for 2-3 minutes. Remove from heat and set aside.

In a bowl, mix ricotta cheese, 1 cup mozzarella cheese, 1/2 cup Parmesan cheese, heavy cream, and chopped parsley until well combined.

Spread a thin layer of Alfredo sauce on the bottom of a 9×13-inch baking dish. Add a layer of lasagna noodles, then spread 1/3 of the cheese mixture over the noodles. Add 1/3 of the seafood mixture on top and drizzle with Alfredo sauce. Repeat this layering process two more times, finishing with noodles and Alfredo sauce on top.

Sprinkle the remaining mozzarella and Parmesan cheese over the top layer. Add breadcrumbs for a crunchy texture. Cover the dish with foil and bake for 25 minutes. Remove the foil and bake for an additional 10-15 minutes, until golden and bubbly.

Let the lasagna sit for 10 minutes before serving. Garnish with additional parsley if desired.