Though the name of this soup implies an Aztec origin, it owes much more of its origin to the Tarascan people from the Michoacán area. Dozens of variations of this soup exist, often featuring a spicy tomato broth with different chillies as the garnish. One much-loved addition is chicharrón, or pork crackling, which works wonderfully well, though in Mexico it can be bought prepared to save one the trouble of the preparation!
1) Toast the chile in a large saucepan over high heat, turning, until fragrant. Remove from saucepan and let cool. Once cool, remove the stem and seeds and break the chile into pieces.
2) Add chile piece and tomatoes to blender and blend until smooth.
3) After removing chiles from saucepan, add oil, garlic and onion. Cook for 8-10 minutes on medium heat. Once golden take garlic and onion and add to blender to puree.
4) Pour puree into saucepan and cook over medium heat until thick, 8-10 minutes.
5) Add chicken or veggie stock, salt and shredded chicken and simmer for 15 minutes to 1 hour on medium-low heat.
6) Prior to serving, garnish with tortilla chips, avocado, cheese, lime, sour cream, etc.