Martha Stewart's Add-On Vinaigrette Dressing

In a small bowl, whisk together vinegar, mustard, salt, pepper, and a pinch of sugar.

Slowly add olive oil, whisking until emulsified. Or shake the ingredients in a jar, or whirl them in a blender.

Variations. For Garlic: Add 1 teaspoon minced garlic or 1/2 clove crushed. For Balsamic: Substitute balsamic vinegar for the wine vinegar. For Lemon Parmesan: Use fresh lemon juice instead of vinegar; add 1/4 cup finely grated Parmesan. For Scallion: Add 3 chopped whole scallions (about 1/4 cup). For Herb: Add 2 tablespoons chopped fresh herbs, such as thyme, parsley, or tarragon. For Blue Cheese: Add 1/2 cup crumbled blue cheese, such as Roquefort.