Pound the chicken breasts to even thickness and season them with salt and pepper. Lightly dredge them in flour. This helps get a golden crust and thickens the sauce later. Shake off the excess flour before cooking.

Heat olive oil in a skillet over medium-high heat. Cook the chicken for about 4–5 minutes per side until golden brown and nearly cooked through. Remove and set aside. Don't overcrowd the pan—do it in batches if needed.

In the same skillet, reduce heat to medium. Add butter, shallots, and garlic, and cook until fragrant, about 2 minutes. Toss in the mushrooms and cook until they release their juices and start to brown—about 6–7 minutes.

Pour in the Marsala wine and scrape up any brown bits from the bottom of the pan. Let it reduce by half, then add chicken broth. Return the chicken to the skillet and simmer everything together for another 5–7 minutes until the sauce thickens.

Sprinkle with fresh parsley and serve immediately. Want an extra glossy sauce? Swirl in a small knob of butter at the end. Trust me, it’s worth it.