Gather and prep all ingredients and set the oven to 375°F.

Cook the lasagna noodles in salted water until just tender. Drain and lay flat on parchment paper lightly drizzled with oil to prevent sticking.

In a large skillet, melt 1 Tbsp butter over medium heat. Sauté onion, celery, and garlic for 5-6 minutes, until softened. Stir in shrimp, imitation crab, spinach, lemon juice, and Cajun seasoning. Cook just until the shrimp turn pink and are cooked through. Remove from heat.

In a small bowl, stir together cottage cheese and parsley. Set aside.

In a medium saucepan, melt ¼ cup butter over medium heat. Whisk in flour and cook for 1 minute.

Slowly pour in the milk, whisking constantly. Bring to a gentle simmer and cook until thickened, about 5-6 minutes.

Stir in Parmesan and Old Bay seasoning. The sauce should be silky and pourable.

Grease a 9x13 baking dish. Spread a thin layer of white sauce on the bottom. Layer 3 noodles slightly overlapping, half of the seafood filling, dollops of cottage cheese mixture, ⅓ of the white sauce, and a sprinkle of mozzarella. Repeat the layers once more. Finish with the last 3 noodles, the remaining sauce, and the rest of the mozzarella.

Cover tightly with foil and bake for 30 minutes. Uncover and bake for another 15-20 minutes. Broil on high for 3-5 minutes, until the cheese is golden.

Let the seafood lasagna rest for 10-15 minutes before slicing. Garnish with any leftover fresh parsley and enjoy.