In a large cast iron skillet, heat the avocado oil over medium-high heat.
Sprinkle both sides of the chicken with sea salt and pepper. Place in the cast iron skillet browning both sides. (Your chicken should not be cooked through yet). Remove from pan and set to the side.
Chop your yellow onion and add to the skillet. Once the onion begins to brown, add the mushrooms and garlic. (See Note Below)
While the vegetables are cooking, in a separate bowl, combine the chicken broth, coconut milk, flour, coconut amino, dried parsley, salt, and pepper. Whisk well until combined. Make sure there are no "clumps" from the flour.
Once your onions have caramelized, add the chicken and pour the sauce into the skillet. Bring everything to a rolling boil and cook for 10-15 minutes. If the sauce isn't thick enough, continue to add 1tsp flour until thick.
Serve with any side! If you are not on paleo, serve over rice!