Season both sides of the chicken halves generously with salt and black pepper. Place the flour in a shallow bowl and dredge each piece of chicken, shaking off any excess.

Heat the olive oil and half of the butter in a large skillet over medium-high heat. Add the chicken and sear for 4–5 minutes per side until a beautiful golden-brown crust forms and it is cooked through. Transfer the chicken to a plate and cover it loosely to keep warm.

Lower the heat to medium and melt the remaining butter in the same skillet. Toss in the sliced mushrooms and cook for 4–5 minutes until they are tender and browned. Add the minced garlic and stir smoothly for 1 minute until highly fragrant.

Pour in the Marsala wine and chicken broth, scraping up any browned bits from the bottom of the pan. Bring the mixture to a simmer and let it reduce by half (about 4–5 minutes). Stir in the heavy cream and let the sauce cook for another 2 minutes until it naturally thickens into a rich, velvety consistency.

Return the seared chicken breasts and any accumulated juices back into the skillet. Spoon the creamy mushroom sauce evenly over the top and let it simmer for 1–2 minutes to heat through.

Use kitchen tongs to smoothly lift a tender, steaming chicken breast—glistening with the rich cream sauce and loaded with mushrooms—and transfer it cleanly onto a dark grey ceramic plate. Garnish with a fresh scatter of chopped parsley and serve immediately.