1-1/2 pounds boneless skinless chicken breasts
salt and pepper to taste
1/2 cup plus 4 teaspoons all-purpose flour divided
4 tablespoons olive oil or as needed, divided
1/4 cup diced shallots
1 teaspoon minced garlic
8 ounces cremini brown button mushrooms, stemmed and sliced
1/2 teaspoon dry thyme or 1 heaping teaspoon fresh thyme leaves
3/4 cup Marsala wine
1 cup low-sodium chicken broth
1 tablespoon butter optional
Italian flat-leaf parsley for garnish
Pound or slice the chicken breasts to 1/4" to 1/2" thickness and cut in half or into smaller portion sized pieces. Season both sides with salt and pepper, to taste.
Add 1/2 cup flour to a shallow dish or bowl (a pie plate works perfectly). Reserve remaining 4 teaspoons flour for later.
Add 3 tablespoons olive oil to a large skillet over MEDIUM-HIGH heat.
Dredge each piece of seasoned chicken breast into the flour, coating both sides, and place into skillet. Cook chicken in batches, if necessary, to avoid overcrowding the skillet. Add additional olive oil between batches, if needed. Cook for approximately 4 to 5 minutes per side, or until nicely browned and cooked through. Transfer chicken to a plate and set aside.
Return skillet to MEDIUM heat and add an additional tablespoon of olive oil . Add the diced shallot. Cook and stir for a minute or two to soften and then add the garlic. Cook and stir for another minute, until fragrant, and then add mushrooms. Saute the mixture for several minutes to soften mushrooms. Season with thyme, salt and fresh ground pepper, to taste and add 4 teaspoons flour to the skillet. Use a whisk to combine the flour and seasonings with the mushroom mixture.
Add the Marsala to the skillet and increase heat slightly to bring to a boil. Cook and whisk for a minute or two at a low boil. Add chicken stock and continue to cook and whisk until sauce is silky and slightly thickened. If you'd like to create an even silkier sauce, add optional butter and allow it to melt into the sauce.
Reduce heat to LOW and return cooked chicken to the skillet, spooning some of the sauce over each piece.
Garnish with chopped parsley and serve.