Step 1

Preheat the oven to 350 degrees F.

Step 2

Grease a 9x13-inch baking dish.

Step 3

In a large skillet over medium heat, sauté the onion in the oil and 2 tablespoons of the butter until tender.

Step 4

Stir the broth and clam juice into the onion mixture.

Step 5

Bring the broth mixture to a boil.

Step 6

Lower the heat and add the scallops, the shrimp, the crab, and 1/8 teaspoon of the pepper.

Step 7

Return the seafood mixture to a boil.

Step 8

Lower the heat and simmer, uncovered, stirring gently, until the shrimp turns pink and the scallops are firm and opaque, about 4-5 minutes. The internal temperature of the seafood should reach 145 degrees F.

Step 9

Drain the seafood mixture, reserving all of the cooking liquid, and set the seafood mixture aside.

Step 10

In a large saucepan, melt the remaining butter.

Step 11

Stir the flour into the melted butter until smooth.

Step 12

In a small bowl, combine the milk and the reserved seafood cooking liquid.

Step 13

Gradually add the milk mixture to the butter and flour mixture.

Step 14

Add the salt and the remaining pepper to the milk mixture.

Step 15

Bring the milk mixture to a boil, cooking and stirring until it is thickened, about 2 minutes.

Step 16

Transfer the milk mixture from the heat and stir in the cream and 1/4 cup of the parmesan cheese.

Step 17

Stir 3/4 cup of the cheese sauce into the seafood mixture.

Step 18

Spread 1/2 cup of the cheese sauce in the prepared baking dish.

Step 19

Layer 3 of the noodles, 1/2 of the seafood mixture, and 1 1/4 cups of the cheese sauce on top of the initial cheese sauce layer in the baking dish.

Step 20

Repeat the layers once.

Step 21

Top the lasagna with the remaining noodles, the remaining cheese sauce mixture, and the remaining parmesan cheese.

Step 22

Bake, uncovered, until golden brown, about 35-40 minutes.

Step 23

Let the casserole stand for 15 minutes.

Step 24

Serve.