In a large mixing bowl, combine the sour cream, mayonnaise, shredded sharp cheddar cheese, garlic powder, onion powder, salt, black pepper, and cayenne pepper if using. Stir the mixture until everything is thoroughly blended and smooth.
Incorporate the Caramelized Onions
Once the onions have cooled to room temperature, fold them gently into the creamy base. Mix well to ensure even distribution of the sweet onions throughout the dip.
Chill for Flavor Fusion
Cover the dip and refrigerate for at least one hour, though for best results, allow it to chill for 3-4 hours or even overnight. This resting period lets all the flavors meld beautifully, resulting in a more robust and cohesive taste.
Garnish and Serve
Just before serving, stir the dip again to bring it back to creamy consistency. Top with freshly chopped chives or parsley for a burst of color and freshness. Serve chilled with your favorite dippers.
