Vinaigrette is a simple blend of oil, vinegar, salt, and pepper. Mustard is also commonly added.
How to Make It
Whisk the ingredients together, shake them in a jar, or combine them in a blender. Traditionally, the salt, pepper, and mustard are whisked into the vinegar first until they dissolve, then the oil is added slowly so the mixture emulsifies. If you're using a blender, put all the ingredients in at the same time.
With vinaigrette, it's the ratio of oil to vinegar that's important, not the specific amounts of each. Three or four parts oil to one part vinegar is the standard. If you like your vinaigrette tart, alter the ratio to two parts oil or equal parts oil and vinegar.
How to Keep It
Vinaigrette keeps in the refrigerator for up to two weeks. The oil and vinegar will separate; just whisk, shake, or whir them to re-emulsify. If the oil has solidified, let the vinaigrette come to room temperature.
Varying the acid will change the taste. Some possibilities are balsamic or sherry vinegar; red-wine, white-wine, or rice vinegar; and fresh lemon, lime, or orange juice. You can make vinaigrette with many oils, including olive, peanut, corn, walnut, and safflower. Match the oil to the food -- a light one, such as safflower, for delicate foods, and a stronger one, like walnut, for full-flavored dishes.
Add an extra flavoring or two, such as herbs, scallions, garlic, cheese, horseradish, poppy or sesame seeds, or a bit of sugar or honey. If you're using fresh herbs, add them just before using the dressing.