• 3/4 cup mayonnaise
• 3/4 cup plain whole-milk yogurt
• 1/2 cup ketchup
• 2 tablespoons cider vinegar
• 3/4 teaspoon freshly ground black pepper

In a medium bowl, whisk together all ingredients. Stir in desired additions. Cover and refrigerate until serving, up to 1 week. Stir before using.

Variations
Season this recipe to your liking with any or all of the following: 2 tablespoons sweet or dill pickle relish; 2 tablespoons minced celery, red onion, or shallots; 2 tablespoons chopped fresh parsley or peeled, seeded, and grated cucumber; 1 tablespoon chopped fresh tarragon.