MAYONNAISE I

1 egg yolk
½ teaspoon dry mustard
½ teaspoon salt
1/16 teaspoon cayenne pepper
1 cup salad oil
2 tablespoons vinegar or lemon juice

Utensils and ingredients should be very cold. Put egg yolk into shallow bowl; add, seasoning and mix well; add oil slowly, almost drop by drop, beating continually until very thick. Thin with vinegar; continue adding oil and vinegar until all is used.