Start by placing each chicken breast between two sheets of plastic wrap or parchment paper. Flatten them gently with a meat mallet or rolling pin to an even thickness of about ½ inch. Season both sides with salt and pepper. Dredge the chicken in the flour to create a light, crispy coating and shake off any excess.

Heat 2 tablespoons of olive oil and 2 tablespoons of butter in a skillet over medium-high heat. Add the chicken breasts and cook for 4–5 minutes on each side until golden brown and cooked through. Remove the chicken from the skillet and set aside.

Add the remaining 2 tablespoons of butter to the same skillet. Toss in the sliced mushrooms and cook them for about 5 minutes until tender and lightly browned. Add the minced garlic and sauté for 1–2 more minutes until fragrant.

Pour in the white wine (or extra chicken broth) and the chicken broth into the skillet. Stir and bring to a simmer, scraping up any browned bits from the bottom of the pan. Allow the mixture to cook for 10 minutes, reducing the liquid by half.

Lower the heat and sprinkle the mozzarella cheese and Parmesan cheese over the mushrooms. Place the seared chicken breasts back into the skillet, positioning them on top of the cheese.

Cover the skillet with a lid and allow everything to simmer for 5–7 minutes. The cheese will melt beautifully, and the chicken will soak up the rich flavors of the sauce. Before serving, sprinkle with fresh parsley for a pop of color and added freshness.