01 - Melt butter in a large skillet over medium heat. Add diced onions, garlic, salt, pepper, and sugar. Sauté, stirring frequently, until onions are deeply golden and caramelized, about 25–30 minutes. Remove from heat and let cool to room temperature.
02 - In a medium bowl, whisk together sour cream, mayonnaise, softened cream cheese, Worcestershire sauce, and cayenne pepper until completely smooth and well combined.
03 - Gently fold the cooled caramelized onions and half of the chopped chives into the cream base. Mix thoroughly to distribute the onions evenly throughout the dip.
04 - Cover the bowl tightly with plastic wrap and refrigerate for at least 1 hour to allow flavors to meld and the dip to firm up slightly.
05 - Transfer the chilled dip to an attractive serving bowl. Sprinkle the remaining chives over the top as a garnish. Serve immediately with potato chips for dipping.