I bought bottled salad dressing for years and never read the label, because I did not want to know. When I finally looked, the second ingredient was some oil I could not pronounce. A cooking class teacher once told me that any dressing is just oil plus acid plus salt, and she was right. Homemade takes two minutes and tastes better than anything in a bottle.

The basic formula

Memorize this and you never need a recipe: three parts oil, one part acid, salt and pepper. That is it. The oil can be olive, avocado, or whatever you have. The acid can be vinegar or lemon juice. Put it in a jar, add a pinch of salt, shake, and taste.

Three dressings I rotate

• Lemon vinaigrette. Olive oil, lemon juice, a squeeze of honey, salt, pepper. Great on greens and chicken.
• Balsamic. Olive oil, balsamic vinegar, a tiny bit of mustard to help it emulsify, salt. The mustard is the trick that keeps it from separating in five seconds.
• Creamy herb. Sour cream or yogurt, a splash of vinegar, garlic powder, dill, salt. It is not exactly ranch, but it is creamy, herby, and takes one minute.

Rules that make it work

Shake it in a jar with a lid, not a bowl with a whisk. The jar does the work and you can store the dressing in the same jar. I keep a small jar with a marker on the lid, and I wash it when it is empty.

Taste before you commit. Acid strength varies, so start with less vinegar and add more if it needs it. And add salt last, taste, then decide, because salt changes how everything else lands.

Fresh dressing separates when it sits, which is normal. A shake before pouring brings it back. Bottled dressings add gums and stabilizers so they never separate, which should tell you something about what is in them.

The two minutes is the honest part. I timed it. The lemon vinaigrette has become my default, and I have not bought a bottle since the day I read that label.