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 until fully melted and smooth.
03 - Gradually stir in shredded white American cheese a handful at a time, whisking constantly until completely melted and the dip is smooth.
04 - Stir in diced jalapeño, green chilies, onion, and garlic. Cook for 2-3 minutes, stirring often, until vegetables soften.
05 - Add ground cumin, chili powder, salt, and white pepper. Adjust seasoning to taste.
06 - Reduce heat to low and keep warm until serving, stirring occasionally. If dip thickens too much, whisk in a splash of milk. Serve warm with tortilla chips, fresh vegetables, or as a nacho topping.