01 - Place chicken breasts between sheets of parchment paper and gently pound to an even ½-inch thickness using a meat mallet or rolling pin.
02 - In a shallow bowl, combine the flour, salt, and pepper. Dredge each chicken breast lightly in the seasoned flour, shaking off any excess.
03 - Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add the chicken and cook for 4 to 5 minutes per side until golden brown and cooked through. Transfer to a plate and cover loosely with foil.
04 - Add the remaining 1 tablespoon of olive oil to the skillet. Sauté the sliced mushrooms for 4 to 5 minutes until deeply browned. Stir in the minced garlic and cook for 30 seconds until fragrant.
05 - Pour in the Marsala wine, scraping up any browned bits from the bottom of the pan. Let the liquid reduce by half, about 2 to 3 minutes.
06 - Add the chicken broth to the skillet and simmer for 3 to 4 minutes, allowing the flavors to meld and the liquid to reduce slightly.
07 - Return the seared chicken to the skillet, spooning the mushroom sauce over the top. Simmer for 3 to 5 minutes until the chicken is heated through and the sauce has thickened to a glossy coating consistency.
08 - Sprinkle generously with chopped fresh parsley and serve immediately while hot.