01 - In a large skillet, melt the butter with olive oil over medium heat. Add the finely chopped onions along with a pinch of salt. Cook, stirring frequently, until the onions turn a deep golden brown and are fully caramelized, approximately 25 to 30 minutes. During the last 2 minutes, stir in the minced garlic. Remove from heat and let the mixture cool completely.
02 - In a large mixing bowl, combine the sour cream, mayonnaise, softened cream cheese, Worcestershire sauce, onion powder, garlic powder, salt, and black pepper. Stir until the mixture is completely smooth and all ingredients are well incorporated.
03 - Gently fold the cooled caramelized onion mixture into the cream base. Mix thoroughly to ensure even distribution throughout the dip.
04 - Cover the bowl tightly and refrigerate for at least 1 hour to allow the flavors to meld together. For the best results, refrigerate overnight.
05 - Before serving, give the dip a good stir. Transfer to a serving bowl and garnish with freshly chopped chives or green onions. Serve chilled with potato chips, pretzels, or an assortment of fresh vegetable sticks.