Bring water to a boil and add seafood seasoning. Add fish, scallops, and shrimp. Reduce heat and simmer for 5 minutes. Drain and save liquid. Mix 1 pound, 13 ounces of powdered milk with 8 1/2 quarts of fish stock (can use part half and half for richer broth). Heat, but do not boil. SAUCE: blend melted butter with flour, salt, paprika and nutmeg in a large skillet. Cook for 3 to 5 minutes to blend and brown. Add reserved liquid and milk. Simmer for 10 to 15 minutes or until thickened. Remove from heat and slowly add egg yolks, stirring constantly. Divide seafood into several casseroles. pour sauce over seafood and keep warm. Serve in tart shells or over toast. Yield: 100 servings.