Melt 4 tablespoons butter in a medium saucepan over medium-low.
Whisk in the flour and cook for 1 minute.
Whisk in the cream and sherry and bring to a simmer over medium-high.
Whisk in the paprika and nutmeg over low heat.
Cook, whisking often, until no floury taste remains, about 5 minutes.
Meanwhile, melt the remaining 4 tablespoons butter in a large saucepan.
Add the scallops and haddock and cook over moderate heat, stirring gently, until the haddock starts to turn white, about 3 minutes.
Add the shrimp and lobster and cook, stirring, for 2 minutes.
Add the cream sauce and simmer over low heat until the seafood is cooked, about 3 minutes longer.
Season with salt and pepper and serve.
