01 - Melt butter in a large skillet over medium heat. Add chopped onions, salt, pepper, and sugar. Cook, stirring frequently, until onions are golden brown and caramelized, about 18–20 minutes. Allow to cool to room temperature.
02 - In a medium bowl, combine mayonnaise, sour cream, cream cheese, Worcestershire sauce, and chives. Mix until completely smooth and creamy.
03 - Add cooled caramelized onions to the cream base. Stir thoroughly to distribute evenly. Taste and adjust seasoning as needed.
04 - Cover bowl and refrigerate for at least 1 hour to allow flavors to meld and intensify.
05 - Transfer dip to serving bowl. Garnish with additional fresh chives. Serve alongside thick-cut potato chips.