You can find dried pasilla chilies at your local Mexican market or the ethnic aisle of a large grocery store. They are inexpensive and add great flavor to many Mexican dishes. If you are using chili powder, skip to step 4
Prepare the pasilla chilies by cutting off then ends and removing the seeds and ribs.
Toast the chili pieces over the flame on your stove or in a broiler for a few seconds - just until they begin to soften and smell toasty.
Place the 28oz can of tomatoes, salt, pepper and 2 teaspoons of ground cumin in a blender
Dice the large onion
Chop the 3 large cloves of garlic
Heat 1 tablespoon of the olive oil in a large pot, add the onions and sauté until they begin to soften - about 5 minutes
Add the garlic and cook for 30 seconds more. If you are using chili powder, add it hear and cook it with the garlic Remove from the heat and let cool slightly
Add the onions and garlic to the blender with the tomato mixture.
Add a couple of the pasilla chili pieces (if you are using them) to the blender
Blend until smooth and taste to adjust the spice and seasonings.
Keep adding chilies (or chili power) a little at a time and blending until the mixture reaches a spice level that works for you.
Heat the other tablespoon of olive oil in the pot and add the tomato mixture from the blender
Bring to a boil, reduce the heat and simmer until the mixture has thickened slightly and the spoon leaves a trail when pulled through - 5-8 minutes
Add the chicken broth and bring to a boil. Reduce the heat and simmer for 15 minutes. Taste and adjust the seasonings
Place the shredded cheese, cilantro, sliced avocado and limes in bowls and get ready to indulge!
Warm the shredded chicken and put 1/3 cup in each bowl
Ladle in the hot, lovely soup over the chicken
Invite everyone to add their favorite combination of toppings along with a couple of crunched up tortilla chips to the soup and enjoy!