Place the cubed cheese, diced tomatoes with chilies and milk in a small 1.5 quart slow cooker.

Cover and cook on low, stirring every 15 minutes, 40 to 50 minutes, until the cheese has fully melted and the mixture looks smooth and glossy, not grainy.

Stir in the shredded Monterey jack and the cumin until completely melted and silky.

Switch to warm for serving and stir every 20 minutes to keep the surface smooth.

If it thickens too much while sitting, stir in an extra splash of milk to loosen it back to a dippable consistency.