Gather all ingredients, including white American cheese, milk or half-and-half, green chiles or jalapeños, cumin, and optional chipotle powder. Decide whether to use a slow cooker or double boiler for cooking.

Set the slow cooker to its lowest setting. Add cheese, milk or half-and-half, green chiles or jalapeños, cumin, and optional chipotle powder directly into the slow cooker. Stir occasionally, letting the mixture heat slowly for 30 minutes to 1 hour until creamy. Adjust consistency by adding more milk or half-and-half as needed. Switch to warm for serving.

Fill the bottom pot with water and heat over medium heat. Add milk or half-and-half, green chiles or jalapeños, cumin, and optional chipotle powder to the top pot. Gradually add the cheese in small pieces, stirring continuously until fully melted and smooth. Adjust consistency by adding more milk or half-and-half if too thick.

Transfer the melted queso dip to a serving bowl. Serve immediately with tortilla chips, or keep warm using a small slow cooker or chafing dish. Enjoy!