Heat oil in a large saucepan over medium heat. Saute tortillas with garlic and epazote over medium heat until tortillas are soft.
Add onion and fresh tomato puree and bring to a boil. Add cumin, chili powder, bay leaves, canned tomato puree and chicken stock. Bring to a boil again, then reduce heat to simmer. Add salt and cayenne pepper to taste, and cook stirring frequently for 30 minutes. Skim fat from surface, if necessary.
Strain and pour into warm soup bowls. Garnish with an equal portion of chicken breast, avocado, shredded cheese and crisp tortilla strips. Serve Immediately.