Magic Mayonnaise

1/4 cup vinegar or lemon juice
1/4 cup vegetable oil or melted butter
2/3 cup sweetened condensed milk
1 egg yolk, unbeaten
1 teaspoon dry mustard
1/2 teaspoon salt
Few grains of cayenne

Place ingredients in a pint jar in the order listed. Fasten top on jar tightly and shake vigorously for 2 minutes. The mixture will blend perfectly. If thicker consistency is desired, place jar in refrigerator to chill before serving. This mayonnaise may also be made by stirring ingredients together in a bowl.