Put one yolk of egg (quite free from any white), half a teaspoonful of salt, and a pinch of cayenne, into a bowl standing in ice. Stir constantly, and add one cupful of pure olive oil, drop by drop. The goodness of the sauce depends upon adding the oil slowly. When it begins to get thick, alternate a few drops of tarragon vinegar with the oil till you have put in one and a half teaspoonfuls of vinegar (lemon juice may be used instead). In summer it is a good plan to mix the yolk of a hard-boiled egg with the raw one; the sauce is made more quickly and is less likely to curdle.
Mayonnaise Monte Bianco Sauce.
To the above Mayonnaise sauce add half a cupful of stiff whipped cream just before serving.
Mayonnaise Sauce ‘alla Ravigote.’
Take a few sprigs of tarragon, parsley, chervil, watercress, two or three chives, and a leaf of spinach or lettuce, and pound them in a mortar with some drops of lemon juice. Squeeze out the juice of the herbs, and mix it with mayonnaise sauce (as above). A few green peas will add to the colour and consistency of the sauce.
Olandese Sauce.
Rub four ounces of butter to a cream in a sauce-pan or a bowl, add four yolks of eggs, beat well together, then put in half a teaspoonful of salt, the juice of half a lemon, a pinch of cayenne, and one cupful of hot water poured in by degrees. Mix well and put into a Bain-marie. Stir until the sauce becomes of the consistency of thick cream, but be careful it does not boil. Take it off the fire and stir for some minutes. ‘Olandese’ sauce ought to be quite smooth and creamy.
‘Alla Panna’ Sauce.
Melt half a pound of butter, add a little flour, salt, pepper, and grated nutmeg. Stir until thick, then add one pint of cream, a little chopped parsley, and heat for five minutes.