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. Stir frequently and cook 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 and cook until fragrant. Remove the skillet from heat and let the onion mixture cool completely to room temperature.
02 - In a large mixing bowl, combine the sour cream, mayonnaise, and softened cream cheese. Add the Worcestershire sauce, onion powder, garlic powder, salt, and freshly ground black pepper. Stir vigorously until the mixture is completely smooth and all seasonings are evenly distributed throughout.
03 - Gently fold the cooled caramelized onion and garlic mixture into the creamy base. Stir thoroughly to ensure the onions are evenly dispersed and the dip has a uniform consistency.
04 - Transfer the dip to an airtight container or cover the mixing bowl tightly with plastic wrap. Refrigerate for at least 1 hour to allow the flavors to meld and the dip to firm up to the ideal spreading consistency.
05 - Remove the dip from the refrigerator and give it a gentle stir. Transfer to a serving bowl and garnish with freshly chopped chives or green onions if desired. Serve chilled alongside potato chips, pretzels, crackers, or an assortment of raw vegetables such as carrots, celery, and bell peppers.