In a bowl, whisk together lemon juice, vinegar, and mustard. Slowly drizzle in the olive oil while whisking to build a stable emulsion. Taste the dressing and add more oil or vinegar, based on your palate. Season with salt and fresh pepper to taste. Makes 1¼ cups. 

Note: The vinaigrette is a great template to work with, Thompson says. Although lemon is the most versatile seasoning and something you'll most likely almost always have on hand, you can swap out different citruses, such as blood orange or grapefruit. You also can switch out the vinegar for alternatives such as apple cider or, for a milder taste, champagne. Furthermore, adding different oils can change the dressing’s profile completely, such as using hazelnut oil or sesame oil. You also can add chopped shallots or garlic; fresh herbs, such as parsley or thyme; or any other fancy stuff you might like.