- Put the chipotle pepper in a small bowl and cover with 1 cup of boiling water. Let it sit until softened, for about 20 minutes. Drain pepper, discarding water, and pat dry. Using a small, sharp knife, cut a lengthwise slit in pepper and scrape out and discard seeds. Coarsely chop pepper and set aside. If you can’t find dried chipotles, substitute canned chipotles in adobo, a spicy tomato sauce. Rinse off the sauce and seed and chop the pepper before adding it to the soup.
- Heat the olive oil in a large, heavy pot over medium heat. When hot, add onion and cook until softened, stirring often, for 4 to 5 minutes. Add garlic and cook, stirring for 1 minute more. Add chopped chipotle, cumin and oregano, tomatoes and stock. Bring mixture to a simmer and cook for 10 minutes. Puree the soup in a food processor or blender and return to the pot (or use an immersion blender to puree the soup in the pot).
- Bring pureed soup to a simmer over medium heat and add the chicken and yellow peppers. Simmer until chicken is cooked through and peppers are tender, for about 5 minutes. Stir in the lime juice, then taste and season with salt as needed.