Instructions

1. Toast chiles in a dry pan over medium-high heat, turning with tongs, until pliable and slightly changed in color (about 30 seconds). Don't use a non-stick for this job.

2. Roast quartered tomatoes, onion and garlic in 350 degree oven for 25 minutes or until they are all nice and mushy.

3. Purée tomatoes, onion, garlic, chiles de arbol (including seeds) and remaining 3 pasilla chiles with 1/2 cup stock in a blender or with a hand mixer, you can do it directly in your soup pot.

4. Heat oil in a large heavy pot over medium heat until it simmers, then cook purée, stirring often until reduced by half and beginning to stick to pot (15 -20 minutes). Reducing means to let half the liquids evaporate so that you end up with less product, but a heavier, more concentrated flavor. Then, stir in remaining 7 1/2 cups of stock, chopped epazote, and 1 teaspoon salt. Simmer uncovered for about half an hour or so.

5. While soup simmers, heat 1 inch of oil to 350 degrees (F) in a deep, 10-inch heavy skillet, then fry tortilla strips a handful at a time until golden (30-45 seconds per batch). Transfer with a slotted spoon to paper towels to drain and season lightly with salt.

6. Divide tortillas and avocado among soup bowls and ladle in soup.