Gather the ingredients.
In a saucepan over low heat, melt butter. Add garlic and cook for 1 minute, or until fragrant.
Slowly pour in milk, allowing it to completely heat through. (It should not come to a boil; keep on low heat.) Once the milk is heated through, begin to slowly add the cheese in small amounts, whisking constantly in between each addition. Make sure the cheese is completely melted before adding the remaining ingredients.
Stir in the jalapeno, cumin, salt, and cayenne pepper. Serve immediately.