A recipe for making hollandaise sauce – One-half cup of salad oil, One onion grated, One teaspoon of paprika, One teaspoon of salt, Five tablespoons of vinegar. Heat slowly until hot and then add Yolks of two eggs. Stir until thick and then add one tablespoon of finely minced parsley. If this should curdle, add two tablespoons of boiling water. Beat hard.