Most of us associate mayonnaise with the stuff in a jar or, if we’re fortunate, an aioli sauce with plenty of garlic. It turns out, however, that mayonnaise is an infinitely versatile sauce that can be flavored with just about anything. The base for all these variations, however, is almost always the same, so once you make a batch of basic unflavored mayonnaise, you can divide it into however many parts you like and flavor the parts. Basic mayonnaise can be made by hand—by slowly working oil into egg yolks—in a blender, or in a food processor. There are a couple of things to look out for. Mayonnaise gets thicker as you add more oil, but if it gets too thick it can separate. So whatever recipe you’re making, add ½ teaspoon of water to the mayonnaise if it starts to get too thick. Don’t add too much water—it takes very little to thin the mayonnaise and keep it from breaking. When you start making the mayonnaise, the oil has to added slowly—in a very thin stream for a food processor or blender and 1 teaspoon at a time when working by hand. Mayonnaise such as aioli, made with extra virgin olive oil, should not be beaten hard by hand, in a blender, or in a food processor—for some reason the violent action makes it bitter. It’s better to make a basic mayonnaise with vegetable oil and then gently stir in extra virgin olive oil by hand.  While mayonnaise is rich—the mayonnaise itself is almost pure oil—it is considerably lighter when combined with vegetables, which convert it into something between a mayonnaise and a salsa.
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