Melt 2 tablespoons butter in the top of a double saucepan; stir in flour until smooth. Add hot milk, stirring constantly until sauce begins to boil. Then reduce heat and simmer for 5 minutes, stirring from time to time. Remove from heat and stir in gelatine, which you have softened in 4 tablespoons cold water. Stir sauce until gelatine is completely dissolved. Then stir in mashed cream cheese and grated Parmesan, and season to taste with salt, freshly ground black pepper and cayenne pepper. Beat egg yolks in one by one and allow the sauce to cool a little. Mix in minced smoked salmon and whipped cream.
Beat egg whites until stiff but not dry. Fold them gently into soufflé mixture. Pour mixture into a soufflé dish which you have prepared in the following manner: butter a strip of waxed paper or foil and tie it around the outside of a well-buttered soufflé dish so that the paper extends 2 inches above the edge of the dish.
Chill soufflé in refrigerator for at least 3 hours. Remove paper or foil “collar” carefully before serving, and sprinkle top of soufflé with crushed walnuts, finely chopped parsley or paprika.