Cook the Chicken: Put chicken breasts in a medium pot, cover them with water, and add some salt. Let it boil for 10-15 minutes until the chicken is cooked.
Shred the Chicken: Take the chicken out of the pot and let it cool for a few minutes. Then, use two forks to shred it into bite-sized pieces.
Cook the Veggies: Heat 4 tablespoons of olive oil in a big Dutch oven. Add the onion, carrots, and celery, and cook for 7 minutes. Then, stir in the garlic for one more minute.
Simmer Everything: Pour in 64 ounces of chicken stock, the diced sweet potatoes, 2 tsp oregano, 2 tsp coriander, 1 tbsp salt, and 1 tsp pepper. Let it all bubble for 12-15 minutes.
Add the Chicken: About halfway through simmering, add the 6 ounces of mushrooms (if you're using them) and all your shredded chicken to the pot.
Finish and Serve: Turn the heat off. Stir in 4-5 cups of spinach until it wilts. Then, stir in ½ cup of half-and-half and a little cayenne pepper if you like. Taste it and serve it up hot!