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 hot milk mixture, whisking constantly until fully melted and smooth.
03 - Gradually stir in shredded white American cheese, one handful at a time. Whisk continuously until completely melted and the dip achieves a smooth, creamy consistency.
04 - Stir in diced jalapeño, green chilies, onion, and garlic. Cook for 2-3 minutes, stirring frequently, until vegetables soften slightly.
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 dip becomes too thick, whisk in a small splash of milk to reach desired consistency.