01 - Combine whole 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, a handful at a time, whisking constantly until fully 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 seasonings as desired.
06 - Reduce heat to low to keep warm, stirring occasionally. If the dip thickens too much, whisk in a small splash of milk. Serve warm with tortilla chips, fresh vegetables, or as a nacho topping.