Large wire whisk or electric blender
3 egg yolks
1 tablespoon wine vinegar or lemon juice (more drops as needed to taste)
1/2 teaspoon salt
1/4 teaspoon dry or prepared mustard
1-1/2 to 2 cups of olive oil, other oil or a mixture of each. If the oil is cold, heat it to tepid; and if you are a novice, use the minimum amount. Macadamia oil works really well and has a milder flavour.
2 tablespoons boiling water