01 - In a medium saucepan over medium-low heat, combine the softened cream cheese and whole milk. Stir continuously with a whisk or wooden spoon until the mixture is completely smooth and free of lumps, approximately 3 to 4 minutes.
02 - Add the shredded cheddar cheese one handful at a time, stirring constantly after each addition. Continue until all the cheese has melted and the dip reaches a silky, uniform consistency.
03 - Stir in the garlic powder, onion powder, smoked paprika, black pepper, cayenne pepper if using, and salt. Maintain gentle heat for 2 to 3 minutes while stirring frequently to prevent the bottom from scorching and to allow the flavors to meld.
04 - Remove the saucepan from heat. Pour the dip into a warmed serving bowl and garnish with freshly chopped chives for a bright, oniony finish.
05 - Serve immediately while warm alongside tortilla chips, crusty bread, breadsticks, or crisp-cut vegetables such as carrots, celery, and bell peppers.