Wash chiles, remove stems and seeds (leave seeds if you prefer a hotter sauce). Place chiles, garlic and onion in a pot and cover with water. Bring to a boil, reduce heat and cook for 45 minutes. Drain water. Place chiles,garlic, onion and flour in a blender and puree till smooth. Pour into saucepan, add 2 cups water and seasonings. Cook over medium heat, stirring contantly, until sauce is thick and bubbly.
Enjoy this delicious red chile sauce Mexican recipe!