Slice and pound the chicken breasts to about ¼ inch thick. Season both sides with kosher salt, black pepper, and Creole seasoning. Set aside.
Season the AP flour with kosher salt and black pepper. Set aside.
In a skillet, heat 2 tablespoons of olive oil and 1 tablespoon of butter over medium-high heat until shimmering. Dredge the chicken in seasoned AP flour, shake off the excess flour, then saute them until golden brown, about 2 minutes on each side. Do this in batches so you don't overcrowd the pan.
Remove the chicken from the skillet and set it aside. Pour off any excess olive oil from the pan but leave the browned fond in the pan
In the same skillet over medium-high heat, add 4 tablespoons butter to the pan.
When the butter begins to bubble, add the mushrooms and about ½ teaspoon of kosher salt. Cook until the mushrooms release their moisture and it evaporates, then continue sautéing until the mushrooms turn slightly brown. This should take about 7 minutes.
Add the garlic, shallots, and dry herbs. Continue to saute' until the garlic is aromatic, about 2 minutes.
Add 2 tablespoons of flour, mix well, and cook for 2 to 3 minutes.
Add the Marsala wine; bring it to a low simmer until it reduces by about 50%; this should take about 5 minutes.
Increase the heat; add the chicken stock, fresh parsley, and fresh herbs. Mix well; when it starts to boil, reduce the heat to a simmer and continue for 5 to 7 minutes while it reduces slightly. Taste the sauce for salt or pepper.
Add the browned chicken plus any accumulated juices back to the pan and spoon sauce over all the chicken pieces.
Remove the skillet from the heat; add the remaining 3 tablespoons of butter to the pan and shake the pan to incorporate the butter into the sauce. Once the butter has melted, it's done.
Notes
Read my article Chicken Marsala for more detailed instructions with photos, Hints and Tips, and serving suggestions.Leftovers: Place leftovers in an airtight container. They can be refrigerated for 2 to 3 days and frozen for up to 3 months. Defrost in the fridge overnight. Reheat in a skillet over medium heat for about 15 minutes or until warmed through. Leftovers can also be reheated in the oven (350 degrees for about 20 minutes) or the microwave. Substitute for chicken breasts: This recipe is great with chicken thighs, thin veal cutlets, pork tenderloin, beef steaks, or fish fillets.