01 - In a medium saucepan over medium heat, combine the whole milk and softened cream cheese. Stir continuously with a whisk or wooden spoon until the cream cheese has fully melted and the mixture is smooth and uniform.
02 - Add the shredded cheddar and Monterey Jack cheese gradually, one handful at a time, stirring constantly after each addition until completely melted before adding more. Continue until all the cheese is incorporated and the dip is silky and creamy.
03 - Stir in the finely chopped jalapeño, diced tomato, chives or green onions, minced garlic, ground cumin, smoked paprika, salt, and pepper. Mix thoroughly until all ingredients are evenly distributed throughout the dip.
04 - Continue cooking for an additional 3 to 5 minutes, stirring frequently to prevent scorching on the bottom, until the dip has thickened slightly and coats the back of a spoon.
05 - Transfer the finished dip to a warm serving bowl. Serve immediately alongside tortilla chips, crusty bread, pretzels, or fresh cut vegetables such as celery, carrots, and bell peppers.