Preheat oven to 175F.
Trim chicken of any visible fat. Make a 1/2 " slit into chicken thigh meat on either side of the chicken
Season the 4 chicken thighs on both sides -with 1/2 teaspoon of salt and 1/2 teaspoon of pepper.
Place chicken, skin side down, on a non-stick skillet or cast iron with a lid, on high heat.
As soon as the chicken starts to sizzle, cover and reduce the heat down to medium - move the thighs around to make sure they aren't sticking to the skillet. Let it cook for about 16-18 minutes.
Prep ingredients – chop onions, chop mushrooms and mince garlic, thyme.
Make sure you check the chicken after 10 minutes. If it browning too fast reduce heat even further, until chicken is cooked. Transfer the thighs to a warm oven.
Pour out all of the chicken fat except for about 2 tablespoons.
Turn the heat to high and then add the onion, garlic, thyme and mushrooms. Sauté, stirring frequently, for about 3 minutes. Add Cajun salt, and then pour in the chicken stock and milk. Continue to cook for 2-3 minute over high heat until the sauce reduces. Adjust seasonings with salt and stock
Sprinkle on some parsley and serve with rice or any side dish.