01 - Combine whole milk and heavy cream in a medium saucepan over medium heat. Bring the mixture just to a simmer without boiling.
02 - Whisk in the cream cheese until completely melted and the mixture is smooth.
03 - Gradually add 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 to 3 minutes with frequent stirring until the 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, stirring occasionally. If the dip becomes too thick, whisk in a small amount of milk to reach the desired consistency. Serve warm with tortilla chips or fresh vegetables.