• 55 ml wine vinegar
• 175 ml olive oil or a mixture of olive and other oils, e.g. sunflower and arachide
• 1 level teaspoon mustard (Dijon or English)
• 1 large clove garlic
• 1 small spring onion (scallion)
• sprig of parsley
• sprig of watercress, optional
• 1 level teaspoon salt
• few grinds of pepper

Put all the ingredients into a blender and run at medium speed for about 1 minute, or mix oil and vinegar in a bowl, add mustard, salt, freshly ground pepper and mashed garlic. Chop the parsley, spring onion and watercress finely and add in. Whisk before serving.