01 - In a medium saucepan set over medium heat, combine the whole milk and softened cream cheese. Stir continuously with a wooden spoon or whisk until the cream cheese has fully melted and the mixture is completely smooth, approximately 3 to 4 minutes.
02 - Gradually add the shredded cheddar and Monterey Jack cheese, one handful at a time, stirring constantly after each addition. Continue until all the cheese has melted and the dip achieves a silky, uniform consistency.
03 - Fold in the chopped jalapeño, diced tomato, chives or green onions, minced garlic, ground cumin, smoked paprika, and season with salt and pepper to taste. Stir thoroughly to distribute all ingredients evenly throughout the dip.
04 - Continue cooking for an additional 3 to 5 minutes, stirring frequently to prevent scorching on the bottom, until the dip thickens slightly and coats the back of a spoon.
05 - Transfer the finished dip to a warm serving bowl and present immediately alongside tortilla chips, crusty bread, pretzels, or an assortment of fresh-cut vegetables such as bell peppers, celery, and carrot sticks.