Pat the chicken dry. Sprinkle a generous pinch of salt and pepper (additional from the amounts listed in the recipe above) over each chicken thigh. In a large skillet, over medium-high heat, warm the oil of choice. I use extra virgin olive oil. Once hot, add the chicken. Brown the chicken on each side for 5 minutes. If the chicken is difficult to flip, let it cook for another minute. The chicken should easily pull away from the skillet when it's perfectly brown on that side. Place the chicken in the slow cooker.
With the stove-top heat still on, add the chopped bell peppers, onions, and chopped garlic to the skillet. Cook for 2-3 minutes, until fragrant. Add this mixture to the slow cooker.
Add all the remaining ingredients, except the fresh cilantro and lime juice, to the slow cooker. Stir the ingredients.
Place the lid on the slow cooker. Cook the soup on high for 4 hours.
After 4 hours, the chicken should be cooked through. Remove the whole chicken thighs from the slow cooker, and shred the chicken with two forks.
Place the shredded chicken back in the slow cooker, and stir in the fresh cilantro and lime juice. Serve warm with any optional toppings.
Notes
*I prefer to use boneless and skinless chicken thighs in this recipe. If you'd like to use bone-in chicken thighs, you'll just need to remove the bones from the chicken before shredding the meat (after about 4 hours of cooking). I don't recommend leaving the skin on the chicken thighs, since the extra fat gives the soup a greasy feel/taste. I also recommend trimming any extra fat on the thighs before browning the meat. **I've been using a red bell pepper in this soup, but any color bell pepper will work. ***I like to rinse the uncooked quinoa under water before adding it to the slow cooker. To do this, rinse the quinoa in a fine mesh sieve under water (about 1-2 minutes). I believe this step helps to take away the bitterness. ****The amount of salt you need in the final soup will depend on the saltines of your broth. I recommend starting with 1 teaspoon and then salting the soup to taste after the 4 hours. If your tomatoes contain salt, you may want to reduce this amount to 1/2 teaspoon, just to be safe, and increase the salt at the end. It's always better to under-salt then to over-salt a slow cooker meal, at least in the beginning. At first, I added 1 cup of quinoa to this soup. This was too much. If you'd like more quinoa, try increasing the amount to 1/2 cup or 2/3 cup. The cooking time will remain the same. This soup is freezer-friendly.