Preheat oven to 350 degrees F.

Place half of the shredded Swiss cheese in the unbaked pie shell.

Layer crabmeat, spinach, and shrimp over the cheese.

Top with the remaining Swiss cheese.

In a large bowl, lightly beat the eggs.

Beat in the heavy cream, half-and-half cream, salt, and cayenne pepper.

Pour the egg mixture over the seafood and cheese in the pie crust.

Bake for 15 minutes.

Reduce the oven temperature to 300 degrees F.

Bake for another 30 minutes, or until a knife inserted in the center comes out clean.

Let the quiche stand for 10 minutes before cutting into wedges and serving.