6 cups water
1 whole skinless/boneless chicken breast
2 teaspoons salt
1 clove garlic
1 medium yellow onion, quartered
2 teaspoons canola oil
1 large yellow onion, chopped
3 medium tomatoes, chopped
1 can (7 ounces) chipotle sauce
2 tablespoons chicken tomato bouillon
12 flat tostada shells packaged or corn tortillas
1 lettuce, finely shredded
1 cup sour cream
1 cup queso fresco, crumbled
In a large stockpot, over medium to high heat, add water, chicken, salt, garlic and onion. Cover and simmer for about 20 minutes. Remove the chicken and allow it to cool. After the chicken cools off shred it. Don't discard broth just yet; you might need it to thin the sauce.
Heat the oil in a large and deep pan over medium heat. Once it is hot but not smoking, stir in the chopped onion and chopped tomatoes and cook until onions are soft and translucent, about 8 minutes. Add the chipotle sauce, chicken bouillon and the cooked shredded chicken; add some of the cooking broth if it is too dry. Bring to a boil, reduce heat and simmer for 5 minutes. Add salt to taste.
Serve on tostada shells with desired toppings.