All I need to make tortilla soup (the Mexican equivalent of "Jewish penicillin") is homemade chicken stock, a few pieces of chicken, seasonal vegetables, diced avocado, a lime, some grated cheese, and tortillas. If you don't want to go through the hassle of frying tortillas, buy crispy tortilla chips. This soup is more like a stew and is a meal in itself. If you want to get fancy, make a batch of hot cornbread to serve alongside.
2 tablespoons vegetable oil
2 large yellow onions, quartered, and thinly sliced
5 cloves garlic, minced
1 whole chicken (3 1/2 pounds), cut into 6 pieces, skin removed
8 cups water
3 large tomatoes, peeled, seeded, and chopped
3 teaspoons ground cumin
2 teaspoons chili powder
1/2 teaspoon chopped fresh oregano
2 bay leaves
2 to 3 tablespoons fresh lime juice
Salt and freshly ground black pepper
Corn oil for frying the tortillas
5 corn tortillas, cut into 1/4-inch strips
2 ounces mozzarella cheese, coarsely grated
2 ounces Monterey Jack cheese, coarsely grated
1 large avocado, diced
1/4 cup sour cream
Heat the oil in a large soup pot over medium heat. Add the onions and cook until soft, about 7 minutes. Add the garlic and cook, stirring, for 1 minute. Add the chicken, water, tomatoes, cumin, chili powder, oregano, and bay leaves. Bring to a boil, reduce heat to low and simmer, uncovered, until the chicken is very tender, about 1 hour. Discard the bay leaves. You should have approximately 6 to 7 cups broth remaining. Remove the chicken from the pan. Remove the meat from the bones and discard the bones. Dice and return the chicken to the pot. Season to taste with the lime juice, salt and pepper.
Heat 1/2 inch corn oil in a deep heavy pan to 375°F on a deep-fat thermometer. Add the tortilla strips and cook until crispy, 1 minute. Remove from the pan and drain on paper towels.
To serve, heat the soup until hot. Ladle into bowls and garnish with the mozzarella, Monterey Jack, and avocado. Top with a spoonful of sour cream and the tortillas strips.