A Vinaigrette is a salad dressing made from oil and vinegar.
Use two parts of oil to one part vinegar: any higher amount of oil and it won’t emulsify into the vinegar. The addition of mustard and of finely chopped ground herbs, onions or garlic will help to both blend everything together and stabilize it so that it stays that way for a while. This added material helps keep oil droplets away from each other and thus pooling back into a component separate from the vinegar.
While drying salad leaves before applying a vinaigrette may seem fussy, there is a reason for it: oil and water repel each other, and if the leaves are wet, your vinaigrette will slide right off.
If you use less milder vinegars such as fruit vinegars, balsamic, etc, you can increase the vinegar ratio and lower the oil ratio, thus making a lower fat vinaigrette without making everyone’s mouth pucker.
Oil and vinegar dressings are nothing new; they were used by the Babylonians and the Egyptians.
Literature & Lore
If you’re wondering why vinaigrette isn’t spelled something like “vinegarette”, which would look more like the word “vinegar”, it’s because the word is derived from the French word for vinegar, “vinaigre”.