Mayonnaise is a thick, creamy sauce made by whisking together oil, egg yolks, and a splash of vinegar or lemon juice. The ingredients might sound simple, but making mayonnaise requires a special technique: you have to add the oil very slowly while whisking constantly, or the mixture will separate instead of turning into that smooth, pale yellow spread.

Mayonnaise is one of the classic French sauces, though people around the world now use it as a sandwich spread, a base for dips and dressings, or a key ingredient in dishes like potato salad and coleslaw. If you've ever eaten a sandwich with a creamy layer between the bread and filling, that was probably mayonnaise. Ranch dressing and tartar sauce both start with mayonnaise as their base.

The word is often shortened to mayo in casual conversation. Some people love it and put it on everything, while others can't stand it. Whether you're Team Mayo or Team No Mayo, there's no denying this sauce has become one of the most common condiments in kitchens and restaurants. Many families keep a jar of store-bought mayo in their refrigerator, though some adventurous cooks enjoy making it fresh at home.