Alexander Sauce (cream sauce with crab and shrimp)

6 tbsp unsalted butter, divided
1/2 cup chopped yellow onion
1 1/2 tbsp flour
2 cups whipping cream
1/2 cup clam juice
1/2 tsp salt
1/4 tsp white pepper
1 dash cayenne pepper
1 cup uncooked small shrimp
5 oz white lump crabmeat

Melt 3 tablespoons of the butter in a large saucepan. Add the onion and cook until soft.

Stir in the flour and cook about 2 minutes, stirring constantly.

Slowly pour in the cream and clam juice. Season with salt, pepper and cayenne. Cook, stirring, about 3 minutes.

In another saucepan, melt the remaining 3 tablespoons butter. Add the shrimp and cook about 2 minutes.

Add the crabmeat and cook about 1 minute. Stir into cream mixture.