In a saucepan, melt butter or margarine over medium heat. Add onions: saute until golden brown, about 10 minutes.
Stir in flour and salt, and mix thoroughly. Gradually add chicken broth, stirring constantly. Cover, and simmer over low heat for about 10 minutes.
When onions are very tender, stir in milk and cream. Heat through. Remove 1/2 cup soup, and mix in egg yolks. Slowly stir egg yolk mixture into soup in pan. Heat through, but do not allow soup to boil. Stir in paprika, black pepper, and red hot pepper sauce. Serve hot, and garnish with chopped parsley.
