In a large pot saute the onion, garlic and chilies in the oil. Add all the other ingredients except the corn starch and bring to a boil. In a cup mix the corn starch with about 1/4 cup of cold water until completely dissolved. Add the corn starch mixture to the boiling mixture. Let simmer for at least half an hour.

To serve pour over crushed tortilla chips and top with grated cheese.

For a spicier version increase cumin to 2 tsp and add 2 tbls soy sauce and 1 tbls worchestershire sauce.