Mix broth, onion, tomato, chiles and garlic. Bring to boil on high heat; cover. Reduce heat to medium and simmer 10 minutes. Take melted butter add to flour. Return this mixture back to heat on the stove and cook 3 minutes. Stir in 3 1/2 cups of the hot milk; add 1/2 cup at a time. Cook 7 minutes until thickened. Remove broth from heat and stir into milk mixture 1/4 cup at a time. Return to heat; add remaining 1 1/2 cups of hot milk, salt and pepper and cheese. Stir until cheese is melted and soup is well heated.