In a large bowl, combine the chilies, about ¾ of the cheddar cheese, the cream cheese, mayonnaise, garlic, salt, pepper, and cumin. Stir until well mixed.
Pour the mixture into a glass or ceramic baking dish (1½ quart capacity or larger). Sprinkle the top with the remaining cheddar.
Bake 25 to 30 minutes, until bubbly and melted. Turn on the broiler for a minute or two to brown the top nicely. Remove and let cool 15 minutes before serving.
Notes
Storage Instructions: Store any leftovers in the fridge, tightly wrapped up, for up to 5 days. It re-heats really nicely so you can enjoy it for several days.