Vinaigrette sauce

Whisk one part vinegar with three parts olive oil, a pinch of salt and black pepper. Add the oil gradually so it emulsifies; Dijon mustard helps it stay together.

Oil and vinegar naturally split when left to stand. Shake it in a jar just before serving, or whisk in a little mustard to help keep the mixture emulsified.

Keep it in a clean, sealed jar in the fridge and use it within about a week. If the oil turns cloudy or solid, let the jar stand at room temperature briefly, then shake well.

A simple oil-and-vinegar dressing suits leafy salads, tomato and cucumber, and steamed green beans. It is also a classic dressing for salade niçoise and works well over lentils or warm potatoes.

Yes: coat vegetables, tofu or meat, then refrigerate while they marinate. Before serving, discard marinade that has touched raw meat; cook the food thoroughly.

Start with about one tablespoon per serving, toss thoroughly, then add a little more only if needed. A light coating brings out the ingredients without leaving a pool of dressing at the bottom.

The names are often used for much the same oil-and-acid dressing, though bottled salad dressings may contain more water, sugar or other ingredients. The listed vinaigrette has 636 kcal per 100 g, compared with 596 kcal for vinaigrette salad dressing.