Mayonnaise.—Crush in a bowl with a wooden spoon about a teaspoonful of mustard flour, half an average teaspoonful each of salt and white pepper, then work into it the yolk of a raw egg (see that a special wooden spoon is kept for mayonnaise making, and that it is well scalded each time of using), and add to it, drop by drop, the very best salad oil, till it is quite as thick as butter; then add about 1½ tea-spoonfuls of vinegar (plain or flavoured, as you please), when it should become quite creamy, and is ready. It should be used at once, but if it must stand a little, stir into the above quantity about a small dessertspoonful of actually boiling water. The above will make half a pint of sauce. If from any cause, such as the too quick pouring in of the oil, etc., the sauce thin or curdle suddenly, the only thing to do is to break another egg into a clean basin and slowly work into it the curdled sauce, almost drop by drop. If stored in a cool place it is possible to keep mayonnaise good for a day or so,