My favorite Mexican cookbook is Authentic Mexican by Rick Bayless. My mother gave Luis and I a copy for Christmas in 1998 and it has become a staple cookbook for me ever since. His cooking shows are really fun to watch as well. In February 2007, I had the opportunity to host a work function in Chicago and jumped at the chance to book his restaurant Topolobampo. For the event we chose the Chef's Tasting menu and one of the items served was the Sopa de Tortilla; I have been craving it ever since. I just want to book a trip back to Chicago so I can eat there again. (Also most amazing margarita I have ever had...yum.)
Since this is a very brothy soup, it is recommended to have a really good broth. Fortunately, my mother insisted I save the bones from the last time I stripped a Costco roast chicken. Her winning argument was that they would make a wonderful broth and she was very right. I took the bones of one chicken carcass and put it in a pot with half an onion, with the root end still attached and 2-3 celery stalks, roughly chopped. I filled the pot with water until it covered everything, loosely covered the pot and let simmer for two hours.
Next I took about eight corn tortillas that I had in the fridge and sliced them first in half and then into thin strips. It is best if you use stale/older tortillas for this as they crisp better when you fry them. Heat 1/3 cup of vegetable oil in a skillet. Set up a cookie sheet with paper towels to have for the cooked tortilla strips. (You don't want to be doing this after the strips are ready to come out because you risk burning them.) I test to make sure the oil is the right temperature by throwing in a small corner of one of the strips - if the oil bubbles vigorously around it then it is the perfect temperature. I then throw in the cut up strips and move them around the pan to keep them separated. I keep an eye on them and continuously move them around until they start turning a deep golden brown. Then I immediately remove them with a slotted spoon and let them cool on the paper towels.
Take 1-2 dried chile pasillas and remove the stems and seeds. Then tear into smaller pieces and soak in a bit of broth. (In this case I actually only had a bag of dried Catarina chiles. the description says they are pungent and have tones of wild berry and tobacco. They are red and will add a complexity of flavor so they fit my bill.) Next, I take out my comal and set it on a high burner. When the comal is hot, I place one medium-small tomato on it and roast it on every side. (Alternately, you can drop it into boiling water for a few minutes.) When the skin is blistered, you will remove it from the comal (or water) and cut the tomato into quarters. Finally remove the seeds and core and throw the tomato into the blender. Next slice one medium onion and rough chop two cloves of garlic. Heat one tablespoon of oil or lard over medium high heat and cook the onion and garlic until both are deep golden brown. Add the cooked onion and garlic and softened chiles with the liquid to the blender with the tomato and process until smooth.
Now after two hours your broth should be pretty flavorful (since the bones were from a roasted chicken you could have probably gotten away with just an hour of boiling). Turn the burner off and using a slotted spoon gently remove the bones, onion and celery. You could also pour this through a strainer into another pan but I try to minimize dirty dishes. Now heat another tablespoon of oil or lard in your skillet and carefully pour the tomato mixture in the pan and constantly stir until the mixture is thicker and darker - about 5 minutes. Add the this mixture to the broth, partially cover and simmer for 30 minutes.
Now set up your bowls with a bit of the crisp tortillas and some cubed or grated cheese (for 6 servings you will need about 2 cups of queso fresco or some sort of soft cheese; Muenster or Monterey Jack.) Right before you are ready to eat, you will ladle some broth directly over these ingredients and serve immediately.
It isn't the simplest soup to make but it sure is memorable. Luis returned from his bicycle ride the following day - he said he had spent much of his return trip just thinking how good a bowl of the soup would be when he got home. Unfortunately it wasn't on the brunch menu!