01 - Combine milk and heavy cream in a medium saucepan over medium heat. Bring just to a simmer without boiling.
02 - Add cream cheese to the simmering milk mixture, whisking constantly until completely melted and smooth.
03 - Gradually stir in shredded white American cheese, adding one handful at a time. Whisk continuously until fully melted and the dip achieves a smooth, uniform consistency.
04 - Stir in diced jalapeño, green chilies, onion, and garlic. Cook for 2-3 minutes with frequent stirring until vegetables begin to soften.
05 - Add ground cumin, chili powder, salt, and white pepper. Taste and adjust seasoning as desired.
06 - Reduce heat to low to keep warm until serving. Stir occasionally to prevent separation. If the dip thickens too much, whisk in a small splash of milk to reach desired consistency. Serve warm with tortilla chips, fresh vegetables, or as a nacho topping.