01 - In a large skillet, melt the butter with olive oil over medium heat. Add the 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 final 2 minutes, stir in the minced garlic. Remove the skillet from heat and let the onion mixture cool completely.
02 - In a mixing bowl, combine the sour cream, mayonnaise, and softened cream cheese. Add the Worcestershire sauce, onion powder, garlic powder, salt, and black pepper. Stir until the mixture is smooth and all ingredients are thoroughly blended.
03 - Gently fold the cooled caramelized onions into the creamy base. Mix until the onions are evenly distributed throughout the dip.
04 - Cover the bowl tightly and refrigerate for at least 1 hour to allow the flavors to meld together.
05 - Before serving, give the dip a good stir. Garnish with finely chopped chives or green onions if desired. Serve chilled alongside potato chips, pretzels, or an assortment of fresh vegetables.