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 to room temperature.
02 - In a 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 evenly incorporated.
03 - Gently fold the cooled caramelized onion mixture into the creamy base until well distributed throughout.
04 - Cover the bowl tightly and refrigerate for at least 1 hour to allow the flavors to meld together fully.
05 - Before serving, give the dip a good stir. Garnish with finely chopped chives or green onions. Serve chilled alongside potato chips, pretzels, or an assortment of fresh crudités.