Write an article based on this summary:

Whisk the remaining ingredients to make a creamy dressing.
Spoon 3/4 cup (174 g) of mayonnaise into a bowl. Add the remaining ingredients and whisk until the seasonings are combined with the mayonnaise. You'll need: 2 tablespoons (24 g) of sour cream 2 tablespoons (3 g) of grated onion 2 tablespoons (24 g) sugar, or to taste 2 tablespoons (30ml) of white vinegar 1 tablespoon (6 g) of dry mustard 2 teaspoons (4 g) of celery seeds Salt and freshly ground pepper to taste