Slice chicken breasts in half horizontally to create cutlets. Pound them lightly to an even thickness.
In a shallow dish, combine flour, salt, and pepper. Dredge chicken cutlets in the flour mixture, shaking off excess.
Heat olive oil and butter in a large skillet over medium-high heat until butter is melted and shimmering.
Add chicken cutlets to the skillet in a single layer, working in batches if necessary. Cook for 3-4 minutes per side, until golden brown and cooked through. Remove chicken from skillet and set aside.
Add sliced mushrooms to the same skillet. Cook, stirring occasionally, until mushrooms are browned and tender, about 5-7 minutes.
Add minced garlic to the skillet and cook for 30 seconds until fragrant.
Pour in the Marsala wine and scrape up any browned bits from the bottom of the skillet. Let the wine simmer and reduce by half, about 2-3 minutes.
Add the chicken broth to the skillet. Bring to a simmer and cook for 5 minutes, or until the sauce has thickened slightly.
Return the chicken cutlets to the skillet and spoon the sauce over them. Heat through for 1-2 minutes.
Garnish with fresh parsley before serving.
Notes
For the best flavor, use a good quality Marsala wine. Sweet Marsala will result in a sweeter sauce, while dry Marsala will yield a more savory sauce.
Ensure your mushrooms are well-browned before adding other ingredients to develop their full flavor.
Serve with your favorite pasta, mashed potatoes, or crusty bread to soak up the delicious sauce.