Salad dressings consist of oil, an acid, and seasonings. The ratio of oil to acid is often 3:1. This means for every three tablespoons of oil, you would use one tablespoon of acid.
A basic dressing is simple and painless. Mix:
6 tablespoons extra virgin olive oil
2 tablespoons lemon juice
1 teaspoon salt
1 teaspoon pepper
1 tablespoon any variety fruit jam or jelly (optional)
For dressings or vinaigrettes, the gold standard of oils is extra virgin olive oil. You can also use canola oil, peanut oil, avocado oil, or sesame oil for Asian-style dressings.
The gold standard of acids is lemon juice or balsamic vinegar. Also, any citrus juice (orange juice and grapefruit juice) works well with vinegar (apple cider or white wine vinegar).
Whisk olive oil and lemon juice together (about 30 seconds). Add salt and pepper. Whisk the jam or jelly into the emulsified dressing (optional). Serve!