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